* tramp-adb.el (tramp-adb-handle-file-attributes):
* tramp-gvfs.el (tramp-gvfs-handle-file-attributes):
* tramp-sh.el (tramp-sh-handle-file-attributes): Return nil in
case of errors.

* tramp.el (tramp-error-with-buffer): Show connection buffer only
when message appeared in minibuffer.  (Bug#18891)
* tramp.el (tramp-check-cached-permissions): Include hop in the
constructed Tramp file name.  (Bug#18943)