Add calls to git_extract_argv0_path() in programs that call git_config_*

Programs that use git_config need to find the global configuration.
When runtime prefix computation is enabled, this requires that
git_extract_argv0_path() is called early in the program's main().

This commit adds the necessary calls.

Signed-off-by: Steffen Prohaska <prohaska@zib.de>
Acked-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

upload-pack.c

@@ -616,6 +616,8 @@ int main(int argc, char **argv)
 	int i;
 	int strict = 0;
 
+	git_extract_argv0_path(argv[0]);
+
 	for (i = 1; i < argc; i++) {
 		char *arg = argv[i];