contrib/ci.inria.fr: revert make distcheck chmod -w on failure

The SCM step of the pipeline may fail in "git clean -fdx"
if some remnants of the previous build are set ro read-only.
make distcheck temporarily sets the source directory to R/O,
revert that to R/W on failure during make distcheck.

Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>
(cherry picked from commit 1341d58)

contrib/ci.inria.fr/job-0-tarball.sh

@@ -1,6 +1,6 @@
 #!/bin/sh
 #
-# Copyright © 2012-2018 Inria.  All rights reserved.
+# Copyright © 2012-2019 Inria.  All rights reserved.
 # See COPYING in top-level directory.
 #
 
@@ -52,7 +52,13 @@ sed	-e 's/^snapshot_version=.*/snapshot_version='$snapshot/ \
 ./autogen.sh
 ./configure
 make
-make distcheck
+
+if ! make distcheck; then
+  # make distcheck temporarily sets the source directory as R/O.
+  # a failure during that R/O step may cause git clean -fdx to fail during the next build
+  chmod u+w -R .
+  false
+fi
 
 # this test requires bash and grep -P, only run it in the main job
 make check -C contrib/windows