core: Fix configuration of remote console socket path.

The remote console socket path is the combination of asterisk.conf
settings astrundir from [directories] and astctl from [files].
Unconditionally combine the two strings after processing all values
to ensure we end up with the correct socket path.

ASTERISK-27415

Change-Id: Ib1e2805d55d6b0955c6430a1a2a93acbf9b091e8