refactor(main): remove the /usr/bin/git invoke, directly use git

commands

Main reason is that this is not really needed and it makes all the
git testing impossible to mock and lead to inconsistent test result
in different environments

dotbare

@@ -67,4 +67,4 @@ case "$1" in
     ;;
 esac
 
-/usr/bin/git --git-dir="${DOTBARE_DIR}" --work-tree="${DOTBARE_TREE}" "$@"
+git --git-dir="${DOTBARE_DIR}" --work-tree="${DOTBARE_TREE}" "$@"

helper/git_query.sh

@@ -19,21 +19,21 @@ function get_commit() {
   local header="${1:-select a commit}"
   local files=("${@:2}")
   if [[ "${#files[@]}" -eq 0 ]]; then
-    /usr/bin/git --git-dir="${DOTBARE_DIR}" --work-tree="${DOTBARE_TREE}" \
+    git --git-dir="${DOTBARE_DIR}" --work-tree="${DOTBARE_TREE}" \
       log --color=always --format='%C(auto)%h%d %s %C(black)%C(bold)%cr' \
       | fzf --no-multi --header="${header}" \
           --preview "echo {} \
           | awk '{print \$1}' \
-          | xargs -I __ /usr/bin/git --git-dir=${DOTBARE_DIR} --work-tree=${DOTBARE_TREE} \
+          | xargs -I __ git --git-dir=${DOTBARE_DIR} --work-tree=${DOTBARE_TREE} \
               show --color=always  __ \
           | ${DOTBARE_DIFF_PAGER}" \
       | awk '{print $1}'
   else
-    /usr/bin/git --git-dir="${DOTBARE_DIR}" --work-tree="${DOTBARE_TREE}" \
+    git --git-dir="${DOTBARE_DIR}" --work-tree="${DOTBARE_TREE}" \
       log --oneline --color=always --decorate=short \
       | fzf --no-multi --header="${header}" --preview "echo {} \
           | awk '{print \$1}' \
-          | xargs -I __ /usr/bin/git --git-dir=${DOTBARE_DIR} --work-tree=${DOTBARE_TREE} \
+          | xargs -I __ git --git-dir=${DOTBARE_DIR} --work-tree=${DOTBARE_TREE} \
               diff --color=always __ ${files[*]} \
           | ${DOTBARE_DIFF_PAGER}" \
       | awk '{print $1}'
@@ -50,7 +50,7 @@ function get_commit() {
 #######################################
 function get_branch() {
   local header="${1:-select a branch}"
-  /usr/bin/git --git-dir="${DOTBARE_DIR}" --work-tree="${DOTBARE_TREE}" branch -a \
+  git --git-dir="${DOTBARE_DIR}" --work-tree="${DOTBARE_TREE}" branch -a \
     | awk '{
         if ($0 ~ /\*.*\(HEAD.*/) {
           gsub(/\* /, "", $0)
@@ -74,7 +74,7 @@ function get_branch() {
             print \$0
           }
         }' \
-      | xargs -I __ /usr/bin/git --git-dir=${DOTBARE_DIR} --work-tree=${DOTBARE_TREE} \
+      | xargs -I __ git --git-dir=${DOTBARE_DIR} --work-tree=${DOTBARE_TREE} \
           log --color=always --color=always --format='%C(auto)%h%d %s %C(black)%C(bold)%cr' __" 
 }
 
@@ -94,7 +94,7 @@ function get_git_file() {
   local print_opt="${2:-full}"
   mydir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
   set_fzf_multi "$3"
-  /usr/bin/git --git-dir="${DOTBARE_DIR}" --work-tree="${DOTBARE_TREE}" \
+  git --git-dir="${DOTBARE_DIR}" --work-tree="${DOTBARE_TREE}" \
     ls-files --full-name --directory "${DOTBARE_TREE}" \
     | fzf --header="${header}" \
         --preview "${mydir}/../helper/preview.sh ${DOTBARE_TREE}/{}" \
@@ -130,7 +130,7 @@ function get_modified_file() {
   local display_mode="${2:-all}"
   local output_format="${3:-name}"
   set_fzf_multi "$4"
-  /usr/bin/git --git-dir="${DOTBARE_DIR}" --work-tree="${DOTBARE_TREE}" \
+  git --git-dir="${DOTBARE_DIR}" --work-tree="${DOTBARE_TREE}" \
     status --porcelain \
     | awk -v display_mode="${display_mode}" '{
         if ($0 ~ /^[A-Za-z][A-Za-z].*$/) {
@@ -147,7 +147,7 @@ function get_modified_file() {
       }' \
     | fzf --header="${header}" --preview "echo {} \
         | awk '{sub(\$1 FS,\"\");print \$0}' \
-        | xargs -I __ /usr/bin/git --git-dir=${DOTBARE_DIR} --work-tree=${DOTBARE_TREE} \
+        | xargs -I __ git --git-dir=${DOTBARE_DIR} --work-tree=${DOTBARE_TREE} \
             diff HEAD --color=always -- ${DOTBARE_TREE}/__ \
         | ${DOTBARE_DIFF_PAGER}" \
     | awk -v home="${DOTBARE_TREE}" -v format="${output_format}" '{
@@ -174,14 +174,14 @@ function get_modified_file() {
 function get_stash() {
   local header="${1:-select a stash}"
   set_fzf_multi "$2"
-  /usr/bin/git --git-dir="${DOTBARE_DIR}" --work-tree="${DOTBARE_TREE}" \
+  git --git-dir="${DOTBARE_DIR}" --work-tree="${DOTBARE_TREE}" \
     stash list \
     | fzf --header="${header}" --preview "echo {} \
         | awk '{
             gsub(/:/, \"\", \$1)
             print \$1
           }' \
-        | xargs -I __ /usr/bin/git --git-dir=${DOTBARE_DIR} --work-tree=${DOTBARE_TREE} \
+        | xargs -I __ git --git-dir=${DOTBARE_DIR} --work-tree=${DOTBARE_TREE} \
             stash show -p __ --color=always \
         | ${DOTBARE_DIFF_PAGER}" \
     | awk '{