Fix overriding of ActivateMasterIp params

In the process of reworking the patches for master, I forgot to remove a
call to GetMasterInfo() that overrides the parameters passed via RPC.
This patch fixes this issue.

Signed-off-by: Andrea Spadaccini <spadaccio@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>