Revert "Generate deprecation warning for postgresql"

Based on resolution [1], there's no clear indication that next
steps involve the removal of the DB from Devstack or from the gate.

[1] I332cef8ec4539520adcf37c6d2ea11488289fcfd

This reverts commit d9aaae95f2b84170bf35e037715e4963d89f940c.

Change-Id: I8410d65c0e0b24035aa035fac7560a686d53ec50
1 file changed