Merge branch 'fix-centos-build-after-pytools-update' into 'master'

Accommodate hidden decorator update in pytools 2019.1 in CentOS build

See merge request inducer/loopy!308

build-helpers/loopy.spec

@@ -15,6 +15,7 @@ import packaging # pip install packaging to add
 a = Analysis(['../bin/loopy'],
              pathex=[expanduser('~/src/loopy')],
              hiddenimports=[
+                "decorator",
                 "appdirs",
                 "packaging.markers",
                 "packaging.specifiers",