update Table._free to use autocommit check

Author: saurabh-hirani

iptc/ip4tc.py

@@ -1362,7 +1362,8 @@ def _free(self, ignore_exc=True):
         if self._handle is None:
             raise IPTCError("table is not initialized")
         try:
-            self.commit()
+            if self.autocommit:
+                self.commit()
         except IPTCError, e:
             if not ignore_exc:
                 raise e