Fix Debian OVS service init script name

I fixed the Debian Open vSwitch service init script name. Due to
differences between versions, I will address this issue in the
Juno version with a separate patch.

Change-Id: I8f1dbe1105cf570322d4fa5911be223c060d9840
Partial-Bug: #1366219
Merge "Fix Debian OVS service init script name" into stable/icehouse