Bug in implementation of ManageObject __eq__ method

Hello.
In my opinion there is potentially a bug in ManagedObject class in eq.

Below is example code that will crash:

from pyVmomi.VmomiSupport import ManagedObject
mo = ManagedObject(moId="1")

if mo != None and mo != "":
    print("Valid ManagedObject")

Output:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "pyVmomi/VmomiSupport.py", line 479, in __ne__
    return not(self == other)
  File "pyVmomi/VmomiSupport.py", line 474, in __eq__
    return self._moId == other._moId and \
AttributeError: 'str' object has no attribute '_moId'

Fixed code:

   def __eq__(self, other):
      if other is None:
         return False
      if not(isinstance(other, ManagedObject)):
         return False
      else:
         return self._moId == other._moId and \
                self.__class__ == other.__class__ and \
                self._serverGuid == other._serverGuid

Start in pyVmomi/VmomiSupport.py at ManagedObject.eq and ne, using the reproduction in the issue to observe the AttributeError when comparing with a string. Verify that comparisons with None and non-ManagedObject values no longer raise, while ManagedObject comparisons still use the existing identity fields.