typing: narrow the scope of some recent disabled import warnings

These comments were added in 39e2b2d062c1, but had the effect of changing the
known type to `Any`, which cascaded through a few function signatures.  Just
ignore the import error instead.

mercurial/chgserver.py

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

mercurial/policy.py

@@ -45,7 +45,7 b" policy: bytes = b'allow'"
 }
 
 try:
-    from . import __modulepolicy__  # type: ignore
+    from . import __modulepolicy__  # pytype: disable=import-error
 
     policy: bytes = __modulepolicy__.modulepolicy
 except ImportError:

mercurial/util.py

@@ -1162,7 +1162,7 b' def makeloggingsocket('
 def version():
     """Return version information if available."""
     try:
-        from . import __version__  # type: ignore
+        from . import __version__  # pytype: disable=import-error
 
         return __version__.version
     except ImportError: