Reset flash_array when viewing screen off off vm summary screen.

Reset flash_array so flash message is not displayed when clicking on links such as Snapshots/Genealogy/Container/Operating System etc from summary screen after perfomring some actions like "Edit Tags".

https://bugzilla.redhat.com/show_bug.cgi?id=1146249
https://bugzilla.redhat.com/show_bug.cgi?id=1102658

@dclarizio please review/test.