[3.7] bpo-41004: Resolve hash collisions for IPv4Interface and IPv6Interface (GH...

[3.7] bpo-41004: Resolve hash collisions for IPv4Interface and IPv6Interface (GH-21033) (GH-21231)

CVE-2020-14422
The __hash__() methods of classes IPv4Interface and IPv6Interface had issue
of generating constant hash values of 32 and 128 respectively causing hash collisions.
The fix uses the hash() function to generate hash values for the objects
instead of XOR operation
(cherry picked from commit b30ee26e366bf509b7538d79bfec6c6d38d53f28)

Co-authored-by: Ravi Teja P <rvteja92@gmail.com>
Signed-off-by: Tapas Kundu <tkundu@vmware.com>