GUACAMOLE-817: Reset keyboard state on navigation and form submission.

Firefox, and perhaps other browsers, does not fire a keyup event for
keys involved in submitting a form. This results in the enter key being
stuck in a pressed state if it is used to submit Guacamole's login
form.

Keyboard state should be reset whenever keyboard state cannot be
reliably maintained. This is already done for loss of window focus, but
should also be done for form submission (this specific case) and
navigation to a different page (generic catch-all).
1 file changed