pytype: work around wrong ImportError flagging

As documented in https://github.com/google/pytype/issues/163, newer versions
of Pytype do not understand caught `ImportError`, so we temporarily ignore
them where applicable.

mercurial/chgserver.py

@@ -151,7 +151,7 b' def _getmtimepaths(ui):'
     """
     modules = [m for n, m in extensions.extensions(ui)]
     try:
-        from . import __version__
+        from . import __version__  # type: ignore
 
         modules.append(__version__)
     except ImportError:

mercurial/policy.py

@@ -37,7 +37,7 b" policy = b'allow'"
 }
 
 try:
-    from . import __modulepolicy__
+    from . import __modulepolicy__  # type: ignore
 
     policy = __modulepolicy__.modulepolicy
 except ImportError:

mercurial/util.py

@@ -1152,7 +1152,7 b' def makeloggingsocket('
 def version():
     """Return version information if available."""
     try:
-        from . import __version__
+        from . import __version__  # type: ignore
 
         return __version__.version
     except ImportError: