check-module-imports: ignore non-stdlib module installed by distribution Previously, the check script would detect breezy as part of the stdlib if installed using the debian package manager. This silence the following complains: tests/test-convert-bzr.t:117: imports not lexically sorted: breezy.bzr.bzrdir < sys tests/test-convert-bzr.t:117: stdlib import "breezy.bzr.bzrdir" follows local import: breezy tests/test-convert-bzr-ghosts.t:7: imports not lexically sorted: breezy.bzr.bzrdir < sys tests/test-convert-bzr-ghosts.t:7: stdlib import "breezy.bzr.bzrdir" follows local import: breezy tests/test-convert-bzr-treeroot.t:7: imports not lexically sorted: breezy.bzr.bzrdir < sys tests/test-convert-bzr-treeroot.t:7: stdlib import "breezy.bzr.bzrdir" follows local import: breezy Differential Revision: https://phab.mercurial-scm.org/D11249