fix autopx regex after recent change

7f451c779645fec1b564b764d237e59808e59616 changed make_quoted_str to repr,
which allowed the string to be either single or double-quoted, which
the regex previously did not handle.

closes  #1024

IPython/extensions/parallelmagic.py

@@ -253,8 +253,7 b' class ParalleMagic(Plugin):'
             ipself.history_manager.store_output(ipself.execution_count)
             # Each cell is a *single* input, regardless of how many lines it has
             ipself.execution_count += 1
-
-        if re.search(r'get_ipython\(\)\.magic\(u?"%?autopx', cell):
+        if re.search(r'get_ipython\(\)\.magic\(u?["\']%?autopx', cell):
             self._disable_autopx()
             return False
         else: