core: modify ctr to be compatible with caller method

SyncLunsInfoForBlockStorageDomainCommand is being called without context
although its constructor is only supported with context parameter,
so we always get a runtime exception when the command is being called.

The proposed fix is to remove the context from the constructor of
SyncLunsInfoForBlockStorageDomainCommand.

Change-Id: Ib06a348beb907da5e1b0c172a36a01fde09bbcbb
Signed-off-by: Daniel Erez <derez@redhat.com>