sig_analog: Eliminate potential timeout with Last Number Redial.

sig_analog: Eliminate potential timeout with Last Number Redial.

If Last Number Redial is used to redial, ensure that we do not wait
for further digits. This was possible if the number that was last
dialed is a prefix of another possible dialplan match. Since all we
did is copy the number into the extension buffer, if other matches
are now possible, there would thus be a timeout before the call went
through. We now complete redialed calls immediaetly in all cases.

Resolves: #1483