Cleanup for pending resource tokens - EUCA-7233

Pending resource tokens are now cleaned up when allocation messages fail
to run.

Added expiration for pending resource tokens after 15 minutes. It is
expected that pending tokens should be cleaned up elsewhere so this is
logged as an error.

EUCA-7233
Merge remote-tracking branch 'origin/dev/sjones/EUCA-7233' into maint/3.3/testing