Delete master IPs from mergee master nodes
Delete master IPs from mergee master nodes

Added a step in cluster-merge that removes the cluster IP from the
master node of the mergee clusters.

Signed-off-by: Andrea Spadaccini <92d490849ac1b40cd8e8878e4d94603bebdb089f@google.com>
Reviewed-by: Michael Hanselmann <68b67885ff74281219b4a4be33cc20fd45078d7c@google.com>

onponomarev/ganeti,yiannist/ganeti,bitemyapp/ganeti,yiannist/ganeti,mbakke/ganeti,ganeti/ganeti,mbakke/ganeti,leshchevds/ganeti,bitemyapp/ganeti,dimara/ganeti,ganeti-github-testing/ganeti-test-1,apyrgio/ganeti,dimara/ganeti,grnet/snf-ganeti,apyrgio/ganeti,andir/ganeti,onponomarev/ganeti,ganeti/ganeti,ganeti-github-testing/ganeti-test-1,andir/ganeti,andir/ganeti,apyrgio/snf-ganeti,yiannist/ganeti,leshchevds/ganeti,leshchevds/ganeti,grnet/snf-ganeti,mbakke/ganeti,apyrgio/snf-ganeti,ganeti/ganeti