Pro upgrade notice is not dismissed when upgrading via FTP

[raamdev]

If you upgrade Comet Cache Pro via FTP, the Dashboard notice that announces a new version is available does not get automatically dismissed.

There needs to be a routine that dismisses any upgrade notice if the current version installed is detected as the latest version.

[jaswrks]

Estimate .25 days.

[jaswrks]

Related comment: #829 (comment)

[jaswrks]

Next Release Changelog:

• Bug Fix: Automatically dismiss any persistent update notifications whenever a new version of the software is recompiled; i.e., don't continue to show an upgrade notice whenever the software has just been updated by a site owner. See also: issue #806 if you'd like additional details.

[jaswrks]

Noting also that these update notifications that are being cleared no longer exist in the current release of the software. The automatic clearing of these persistent notifications is to clear them on old installations of Comet Cache.