xmpp_conn_set_flags() argument is a long

Correct the type for the flag argument from int to long. Note the
compiler will still complain because, although xmpp_conn_set_flags() is
declared to take a signed long, the constants are declared as unsigned
longs:

src/xmppipe.c: In function ‘main’:
src/xmppipe.c:205:13: warning: conversion to ‘long unsigned int’ from
‘long int’ may change the sign of the result [-Wsign-conversion]
       flags |= XMPP_CONN_FLAG_TRUST_TLS;
             ^
src/xmppipe.c:205:16: warning: conversion to ‘long int’ from ‘long
unsigned int’ may change the sign of the result [-Wsign-conversion]
       flags |= XMPP_CONN_FLAG_TRUST_TLS;

src/xmppipe.c

@@ -75,7 +75,7 @@ int main(int argc, char **argv) {
   char *pass = NULL;
   char *addr = NULL;
   u_int16_t port = 0;
-  int flags = 0;
+  long flags = 0;
 
   int ch = 0;