Call addProfile after a path has been set for a new profile

When saving the fallback profile to a new profile, we have to delay
calling addProfile until after a path has been set for the new profile.
This is because ProfileModel::populate calls ProfileManager::sortProfiles,
and the latter skips profiles that have path == FALLBACK/ .

This also seems to take care of duplicate entries in "Switch Profile"
menu, with respect to the fallback profile after saving.