Revert "Install `salt-api` scripts if `salt-master` is installed."

salt-api isn't installed by default (see lines 2150, 2298, etc), but this commit attempts to restart the salt-api service whenever the master is installed. In lieu of always installing salt-api implicitly, back this change out to make salt-api optional.

This reverts commit 0577622dad6acb379250df76bb6605312116662f.