Make fetch/pull scripts terminate cleanly on errors

Don't continue with a merge if the fetch failed.

git-fetch-script

@@ -35,7 +35,7 @@ download_objects () {
 }
 
 echo "Getting remote $merge_name"
-download_one "$merge_repo/$merge_name" "$GIT_DIR"/MERGE_HEAD
+download_one "$merge_repo/$merge_name" "$GIT_DIR"/MERGE_HEAD || exit 1
 
 echo "Getting object database"
-download_objects "$merge_repo" "$(cat "$GIT_DIR"/MERGE_HEAD)"
+download_objects "$merge_repo" "$(cat "$GIT_DIR"/MERGE_HEAD)" || exit 1

git-pull-script

@@ -15,7 +15,7 @@ fi
 : ${GIT_DIR=.git}
 : ${GIT_OBJECT_DIRECTORY="${SHA1_FILE_DIRECTORY-"$GIT_DIR/objects"}"}
 
-git-fetch-script "$merge_repo" "$merge_head"
+git-fetch-script "$merge_repo" "$merge_head" || exit 1
 
 git-resolve-script \
 	"$(cat "$GIT_DIR"/HEAD)" \