Merge pull request #5507 from scientificlinux/sl7

Update sl container for sl7 to current (build-date=20190304)

library/sl

@@ -8,7 +8,7 @@ Tags: 7, latest
 Architectures: amd64
 GitFetch: refs/heads/7
 Directory: sl7
-GitCommit: f9b2676de2c0c6258a2016f5e844a073a442d27d
+GitCommit: 4cded445e59d1f132c8d478cad331879053b272c
 
 # For the SL6 container
 Tags: 6