repository: remove unnecessary include of path.h

This also made it clear that several .c files that depended upon path.h
were missing a #include for it; add the missing includes while at it.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

http-backend.c

@@ -4,6 +4,7 @@
 #include "environment.h"
 #include "git-zlib.h"
 #include "hex.h"
+#include "path.h"
 #include "repository.h"
 #include "refs.h"
 #include "pkt-line.h"