Don't check for new versions of pip.

--- pip-19.1/src/pip/_internal/cli/base_command.py
+++ pip-19.1/src/pip/_internal/cli/base_command.py
@@ -213,12 +213,8 @@ class Command(object):
 
             return UNKNOWN_ERROR
         finally:
-            allow_version_check = (
-                # Does this command have the index_group options?
-                hasattr(options, "no_index") and
-                # Is this command allowed to perform this check?
-                not (options.disable_pip_version_check or options.no_index)
-            )
+            # Disabled on Gentoo
+            allow_version_check = False
             # Check if we're using the latest version of pip available
             if allow_version_check:
                 session = self._build_session(