Fix travis issue due to errno

errno and EMFILE are provided by <unistd.h>, but we need log.h anyway,
which includes logger.h, and which includes <unistd.h> in turn.

tests/testproxy/lp/prototcp.c

@@ -29,6 +29,7 @@
 
 #include "prototcp.h"
 #include "sys.h"
+#include "log.h"
 
 #include <sys/param.h>
 #include <string.h>