python: Fix rich comparisons

Python 3 doesn't call objects __cmp__() methods any more to compare
them. Instead, it requires implementing the rich comparison methods
explicitly: __eq__(), __ne(), __lt__(), __le__(), __gt__() and __ge__().

Fortunately Python 2 also supports those.

This commit only implements the comparison methods which are actually
used by the build scripts.

Signed-off-by: Mathieu Bridon <bochecha@daitauha.fr>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>

src/intel/vulkan/anv_extensions.py

@@ -160,14 +160,15 @@ class VkVersion:
         patch = self.patch if self.patch is not None else 0
         return (self.major << 22) | (self.minor << 12) | patch
 
-    def __cmp__(self, other):
+    def __gt__(self, other):
         # If only one of them has a patch version, "ignore" it by making
         # other's patch version match self.
         if (self.patch is None) != (other.patch is None):
             other = copy.copy(other)
             other.patch = self.patch
 
-        return self.__int_ver().__cmp__(other.__int_ver())
+        return self.__int_ver() > other.__int_ver()
+
 
 
 MAX_API_VERSION = VkVersion('0.0.0')