Bug fix: if configuration file can't be opened for writting, return error instead of exit.

git-svn-id: http://voip.null.ro/svn/freesentral/trunk@221 5c761656-935b-0410-a7a0-fdd7172080e0
Bug fix: if write error when configuring network interface, restart network.

git-svn-id: http://voip.null.ro/svn/freesentral/trunk@222 5c761656-935b-0410-a7a0-fdd7172080e0