QPID-4826: Patch Perl bindings memory leak

Marked the VariantToPerl() method in swig_perl_typemaps.i as returning a
new object, which indicates to the Perl bindings that it needs to keep
track of the return value for garbage collection.

Also removed the Swig 1.3.32 minimum restriction to enable building on
RHEL5 systems.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1481021 13f79535-47bb-0310-9956-ffa450edef68