rds_mysql -> rds-mysql

[#48753337]
Attempt to fix broken services deploy.

We left the name of the job with an underscore, but changed property
lookup to assume a hyphen. Reverting property lookup to use an
underscore to match the job name.

[#48753337]
Yet another attempt to edit the template.

There were property lookup references hardcoded we missed in the last
fix attempt.

[#48753337]
Revert "Yet another attempt to edit the template."

This reverts commit 88bd7401376fb62fd715efb79f0f0d1e55e6a63f.
Revert "Attempt to fix broken services deploy."

This reverts commit 9f76a4b6b639d4244c1d48856038e32c97a35ae5.
Revert "rds_mysql -> rds-mysql"

This reverts commit fe1c14d7131895c11cb0c0cda44df88961c53c90.
One more stab at a deployment issue
Replace hard-coded stemcell version to latest alias