fix failing tests without X in IPython.lib

note that pylab_not_importable appears to not be enough to catch if
we're running X. I'm able to import pylab, and it's only %%matplotlib
magic that causes these tests to die

IPython/lib/tests/test_irunner_pylab_magic.py

@@ -66,6 +66,7 b' class RunnerTestCase(unittest.TestCase):'
         self.assertTrue(mismatch==0,'Number of mismatched lines: %s' %
                         mismatch)
 
+    @decorators.skip_if_no_x11
     @decorators.skipif_not_matplotlib
     @decorators.skipif(pylab_not_importable, "Likely a run without X.")
     def test_pylab_import_all_enabled(self):
@@ -92,6 +93,7 b' Out\\[6\\]: True'
         runner = irunner.IPythonRunner(out=self.out)
         self._test_runner(runner,source,output)
 
+    @decorators.skip_if_no_x11
     @decorators.skipif_not_matplotlib
     @decorators.skipif(pylab_not_importable, "Likely a run without X.")
     def test_pylab_import_all_disabled(self):