core: Remove IsVdsWithSameIpExistsQurey

This patch removes the unused IsVdsWithSameIpExistQuery.

Removed in this patch:
1. The IsVdsWithSameIpExistQuery class.
2. The IsVdsWithSameIpExistParameters class only used by the
   aforementioned query.
3. The IsVdsWithSameIpExist constant from VdcQueryType corresponding
   to the aforementioned query.
4. The isVdsWithSameIpExists and isVdsWithSameIpExsitsStatic methods
   in VdsHandler which are no longer in use.

Change-Id: Ife14c2758c8f46b244a32ac67747aecbf9d799b4
Signed-off-by: Allon Mureinik <amureini@redhat.com>