unpack out,err in ipexec

Code reflected the possibility that getoutputerror could return None,
but this is no longer the case.  It always returns two strings.

IPython/testing/tools.py

@@ -216,14 +216,12 b' def ipexec(fname, options=None):'
     full_fname = os.path.join(test_dir, fname)
     full_cmd = '%s %s %s' % (ipython_cmd, cmdargs, full_fname)
     #print >> sys.stderr, 'FULL CMD:', full_cmd # dbg
-    out = getoutputerror(full_cmd)
+    out, err = getoutputerror(full_cmd)
     # `import readline` causes 'ESC[?1034h' to be output sometimes,
     # so strip that out before doing comparisons
     if out:
-        out,err = out
         out = re.sub(r'\x1b\[[^h]+h', '', out)
-        out = out,err
-    return out
+    return out, err
 
 
 def ipexec_validate(fname, expected_out, expected_err='',