core: Modify constructor to be compatible with caller method

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

The proposed fix is to add a constructor which also supports to get only
paramteres

Change-Id: Ic120c4b33b40a122895c2088b8365f26c05eb517
Signed-off-by: Maor Lipchuk <mlipchuk@redhat.com>