TALM and BMER build should only be built when there are new changes

Description of problem:

Open this Jira to address following two scenarios in TALM and BMER builds:

• New commits merged, but somehow the repo pull did not happen, thus new build does not contain expected commits. - If repo pull build was not run, then no brew bundle build should be generated, otherwise it can have negative impact on bug verification and failure investigations.
• No new commits merged - in this case, no build should be generated as well, otherwise the build attached to the errata will mostly likely be different than the tested version.

Expected result: a new build should always contain new commits compared to last build off the same branch.

Version-Release number of selected component (if applicable):

4.11