Made postgres module initdb dependency optional
Made postgres module initdb dependency optional

On some distros (like ubuntu, debian) initdb is
not in the $PATH and is provided by the server
package.

The initdb dependency would require that the
server package be installed to manage remote
databases which is not optimal.

Issue reported by @ticosax in pull request
https://github.com/saltstack/salt/pull/30537#issuecomment-185675050

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt