http-fetch: add missing initialization of argv0_path

According to c6dfb399 (remote-curl: add missing initialization of
argv0_path, 2009-10-13), programs with "main" must call this to
work correctly on MinGW.
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

http-fetch.c

 #include "cache.h"
+#include "exec_cmd.h"
 #include "walker.h"
 
 int main(int argc, const char **argv)
@@ -19,8 +20,8 @@ int main(int argc, const char **argv)
 	int get_verbosely = 0;
 	int get_recover = 0;
 
+	git_extract_argv0_path(argv[0]);
 	prefix = setup_git_directory();
-
 	git_config(git_default_config, NULL);
 
 	while (arg < argc && argv[arg][0] == '-') {