systemd: use Wants for the dependency btw. osmo-bsc-mgcp and osmo-bsc

* osmo-bsc and osmo-bsc-mgcp are needed to run
* with Wants, both are started but can be indepently
  controlled via systemctl

Fixes: SYS#738
1 file changed
tree: 690d70bbae2e1760638a756200c6c798b1f75198
  1. debian/
  2. hlrsync/
  3. linux-kernel/
  4. openbsc/
  5. wireshark/
  6. README