Fix: missing method on test class from another module raises Error

This is a fix for the following issue:

Attempting to run a non-existent method on a test class that has been imported from another module results in an ugly error. For instance:

    $ _virtualenv/bin/nosetests tests/remote_tests.py:RemoteTests.can_restart_vm -v
    Traceback (most recent call last):
      File "_virtualenv/bin/nosetests", line 9, in <module>
        load_entry_point('nose==1.2.1', 'console_scripts', 'nosetests')()
      File "/home/mick/Programming/current/peachtree/_virtualenv/src/nose/nose/core.py", line 118, in __init__
        **extra_args)
      File "/usr/lib/python2.7/unittest/main.py", line 94, in __init__
        self.parseArgs(argv)
      File "/home/mick/Programming/current/peachtree/_virtualenv/src/nose/nose/core.py", line 169, in parseArgs
        self.createTests()
      File "/home/mick/Programming/current/peachtree/_virtualenv/src/nose/nose/core.py", line 183, in createTests
        self.test = self.testLoader.loadTestsFromNames(self.testNames)
      File "/home/mick/Programming/current/peachtree/_virtualenv/src/nose/nose/loader.py", line 475, in loadTestsFromNames
        return unittest.TestLoader.loadTestsFromNames(self, names, module)
      File "/usr/lib/python2.7/unittest/loader.py", line 128, in loadTestsFromNames
        suites = [self.loadTestsFromName(name, module) for name in names]
      File "/home/mick/Programming/current/peachtree/_virtualenv/src/nose/nose/loader.py", line 423, in loadTestsFromName
        return self.loadTestsFromName(addr.call, module)
      File "/home/mick/Programming/current/peachtree/_virtualenv/src/nose/nose/loader.py", line 390, in loadTestsFromName
        obj = getattr(parent, obj.__name__)
    AttributeError: 'Failure' object has no attribute '__name__'

Whereas the expected output is:

    $ _virtualenv/bin/nosetests tests/remote_tests.py:RemoteTests.can_restart_vm -v
    Failure: ValueError (No such test RemoteTests.can_restart_vm) ... ERROR

    ======================================================================
    ERROR: Failure: ValueError (No such test RemoteTests.can_restart_vm)
    ----------------------------------------------------------------------
    Traceback (most recent call last):
      File "/home/mick/Programming/current/peachtree/_virtualenv/src/nose/nose/failure.py", line 39, in runTest
        raise self.exc_class(self.exc_val)
    ValueError: No such test RemoteTests.can_restart_vm

    ----------------------------------------------------------------------
    Ran 1 test in 0.001s

    FAILED (errors=1)