remote: improved error reporting

Several places in the remote code identify an error and then swallow it;
return the error.

src/fetch.c

@@ -87,10 +87,10 @@ static int filter_wants(git_remote *remote, const git_fetch_options *opts)
 			goto cleanup;
 	}
 
-	if (git_repository_odb__weakptr(&odb, remote->repo) < 0)
+	if ((error = git_repository_odb__weakptr(&odb, remote->repo)) < 0)
 		goto cleanup;
 
-	if (git_remote_ls((const git_remote_head ***)&heads, &heads_len, remote) < 0)
+	if ((error = git_remote_ls((const git_remote_head ***)&heads, &heads_len, remote)) < 0)
 		goto cleanup;
 
 	for (i = 0; i < heads_len; i++) {

src/push.c

@@ -291,7 +291,7 @@ static int queue_objects(git_push *push)
 		if (git_oid_equal(&spec->loid, &spec->roid))
 			continue; /* up-to-date */
 
-		if (git_odb_read_header(&size, &type, push->repo->_odb, &spec->loid) < 0)
+		if ((error = git_odb_read_header(&size, &type, push->repo->_odb, &spec->loid)) < 0)
 			goto on_error;
 
 		if (type == GIT_OBJECT_TAG) {
@@ -301,19 +301,19 @@ static int queue_objects(git_push *push)
 				goto on_error;
 
 			if (git_object_type(target) == GIT_OBJECT_COMMIT) {
-				if (git_revwalk_push(rw, git_object_id(target)) < 0) {
+				if ((error = git_revwalk_push(rw, git_object_id(target))) < 0) {
 					git_object_free(target);
 					goto on_error;
 				}
 			} else {
-				if (git_packbuilder_insert(
-					push->pb, git_object_id(target), NULL) < 0) {
+				if ((error = git_packbuilder_insert(
+					push->pb, git_object_id(target), NULL)) < 0) {
 					git_object_free(target);
 					goto on_error;
 				}
 			}
 			git_object_free(target);
-		} else if (git_revwalk_push(rw, &spec->loid) < 0)
+		} else if ((error = git_revwalk_push(rw, &spec->loid)) < 0)
 			goto on_error;
 
 		if (!spec->refspec.force) {

src/remote.c

@@ -1088,7 +1088,7 @@ int git_remote_download(git_remote *remote, const git_strarray *refspecs, const
 	if (ls_to_vector(&refs, remote) < 0)
 		return -1;
 
-	if ((git_vector_init(&specs, 0, NULL)) < 0)
+	if ((error = git_vector_init(&specs, 0, NULL)) < 0)
 		goto on_error;
 
 	remote->passed_refspecs = 0;