remote functions: return an int

Stop returning a void for functions, future-proofing them to allow them
to fail.

include/git2/remote.h

@@ -378,8 +378,9 @@ GIT_EXTERN(int) git_remote_connected(const git_remote *remote);
  * the operation has been cancelled and if so stops the operation.
  *
  * @param remote the remote
+ * @return 0 on success, or an error code
  */
-GIT_EXTERN(void) git_remote_stop(git_remote *remote);
+GIT_EXTERN(int) git_remote_stop(git_remote *remote);
 
 /**
  * Disconnect from the remote
@@ -387,8 +388,9 @@ GIT_EXTERN(void) git_remote_stop(git_remote *remote);
  * Close the connection to the remote.
  *
  * @param remote the remote to disconnect from
+ * @return 0 on success, or an error code
  */
-GIT_EXTERN(void) git_remote_disconnect(git_remote *remote);
+GIT_EXTERN(int) git_remote_disconnect(git_remote *remote);
 
 /**
  * Free the memory associated with a remote

src/remote.c

@@ -1676,20 +1676,24 @@ int git_remote_connected(const git_remote *remote)
 	return remote->transport->is_connected(remote->transport);
 }
 
-void git_remote_stop(git_remote *remote)
+int git_remote_stop(git_remote *remote)
 {
 	assert(remote);
 
 	if (remote->transport && remote->transport->cancel)
 		remote->transport->cancel(remote->transport);
+
+	return 0;
 }
 
-void git_remote_disconnect(git_remote *remote)
+int git_remote_disconnect(git_remote *remote)
 {
 	assert(remote);
 
 	if (git_remote_connected(remote))
 		remote->transport->close(remote->transport);
+
+	return 0;
 }
 
 void git_remote_free(git_remote *remote)