gdb: don't barf on non-ASCII text in SwTxtNode

Because the default text encoding in Python 2 is "ascii" these would
throw a UnicodeEncodeError: 'ascii' codec can't encode character...

solenv/gdb/libreoffice/sw.py

@@ -100,7 +100,7 @@ class BigPtrArrayPrinter(object):
                 # accessing this is completely non-obvious...
                 # also, node.dynamic_cast(node.dynamic_type) is null?
                 value = "    TextNode " + \
-                    str(node.cast(node.dynamic_type).dereference()['m_Text'])
+                  unicode(node.cast(node.dynamic_type).dereference()['m_Text'])
             elif str(node.dynamic_type.target()) == "SwOLENode":
                 value = "     OLENode "
             elif str(node.dynamic_type.target()) == "SwGrfNode":