Check repository format version in enter_repo().

After daemon, upload-pack and receive-pack find out where the
git directory is and chdir() there, make sure that repository is
in a format we understand, after putenv("GIT_DIR=.") so that it
knows to pick up the configuration file from there.

Signed-off-by: Junio C Hamano <junkio@cox.net>

path.c

@@ -199,6 +199,7 @@ char *enter_repo(char *path, int strict)
 	if(access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
 	   validate_symref("HEAD") == 0) {
 		putenv("GIT_DIR=.");
+		check_repository_format();
 		return current_dir();
 	}