swig-py: follow up to r1912500: Fix NameError on using old SWIG

As some old version of SWIG does not import libsvn.core or core sub-module
in generated svn_delta.py, it need to import libsvn.core before using  
libsvn.core.svn_pool_create().

* subversion/bindings/swig/svn_delta.i (SWIGPYTHON: _ItemBaton.__init__):
  Import libsvn.core explicitly. 


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1928521 13f79535-47bb-0310-9956-ffa450edef68
1 file changed