Fix hostDomainGenerator.sh error about localhost socket creation

BZ: 171573

If localhost is not bound to 127.0.0.1, socket creation fails in the
portAllocator.py script. This error is not well catched in the main
tool hostDomainGenerator.sh.

This patch updates portAllocator.py so that the IP address 127.0.0.1
is used instead of localhost. In addition, the potential error messages
raised by portAllocator.py are now correctly taken into account by
hostDomainGenerator.sh. HostDomainGenerator.sh has also been updated
to replace all instances of 'localhost' by '127.0.0.1'.

Change-Id: I7ed6ede7a1148360efac4bf38f49054066a50a29
Signed-off-by: Frédéric Boisnard <fredericx.boisnard@intel.com>