core: removal of unneeded  line in fixtures.xml

Change-Id: I76c6c9a1a7af24b053d2da999830b2a9d9593207
Signed-off-by: Liron Aravot <laravot@redhat.com>
core: avoid connect to the same target multiple times

When querying for the storage server connections of a VG, there's no
need to return the same connection multiple times if the it's the same
to avoid multiple operations on engine and on vdsm side. As we currently
have one session for target, so this shouldn't cause to regression while
eliminating unneeded operations.

before:
-------
engine:
START, ConnectStorageServerVDSCommand connectionList =
[{ id: 1212f182-9593-4cef-8c98-a3e99bf29fa2... };
{ id: 1212f182-9593-4cef-8c98-a3e99bf29fa2... };
{ id: 1212f182-9593-4cef-8c98-a3e99bf29fa2, ... };]),

vdsm:
Run and protect: connectStorageServer, Return response: {'statuslist':
[{'status': 0, 'id': '1212f182-9593-4cef-8c98-a3e99bf29fa2'}, {'status':
0, 'id': '1212f182-9593-4cef-8c98-a3e99bf29fa2'}, {'status': 0, 'id':
'1212f182-9593-4cef-8c98-a3e99bf29fa2'}]}

after:
-------
engine:
connectionList = [{ id: 1212f182-9593-4cef-8c98-a3e99bf29fa2, ..};])

vdsm:
Run and protect: connectStorageServer, Return response: {'statuslist': [{'stat
us': 0, 'id': '1212f182-9593-4cef-8c98-a3e99bf29fa2'}]}

Change-Id: If40ef468dc4eca4237ad824dc81aa39a90cce017
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1111994
Signed-off-by: Liron Aravot <laravot@redhat.com>