Add missing parentheses on 'print' (gdb.python/py-progspace.exp)

Add missing parentheses on 'print' (gdb.python/py-progspace.exp)

Commit 33d569b709886a1208145806da80b689d9cae9da ("gdb/python: Return
None from Progspace.block_for_pc on error") added a few tests on
gdb.python/py-progspace.exp which use 'print', but forgot to use
parentheses when passing the arguments to be printed.  This fails on
Python 3.

This commit adds these missing parentheses.  Pushed as obvious.

gdb/testsuite/ChangeLog:
2019-11-20  Sergio Durigan Junior  <sergiodj@redhat.com>

	* gdb.python/py-progspace.exp: Add missing parentheses on some
	'print' commands.

Change-Id: Iac0a7578855d128bbee3b98e7ea5888dae55fc00