fixed memcheck using valgrind on remote device

Change-Id: Ie2ded39c73dce99db574b16cb8e0e1ffb7ba2415
Reviewed-by: hjk <hjk121@nokiamail.com>
Add <platform> element to pluginspec-files.

The <platform> element may contain a regular expression
matching the names of the platforms on which the plugin works.

Task-number: QTCREATORBUG-9002
Change-Id: Ic816cfed69a5dd2c4112c976843b9106ba2cbd22
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
Reviewed-by: hjk <hjk121@nokiamail.com>