Fix EZP-22894: 5.3-rc7 has development settings enabled

With switch to composer based model we no longer have the option
to swap to many things in builds anymore, and hence we herby
swap the defaults in git to be same as in builds.
Merge pull request #972 from ezsystems/prod_settings_by_default

Fix EZP-22894: 5.3-rc7 has development settings enabled