dist: tolerate sysctl failures

sysctl may fail in a container environment if /proc is not virtualized
properly.

Fixes #1990
Message-Id: <20170625145930.31619-1-avi@scylladb.com>

dist/debian/debian/scylla-kernel-conf.postinst

@@ -7,7 +7,8 @@ KVER=$(uname -r)
 if [[ $KVER =~ 3\.13\.0\-([0-9]+)-generic ]]; then
     echo "kernel $KVER detected, skip running sysctl..."
 else
-    sysctl -p/etc/sysctl.d/99-scylla-sched.conf
+    # expect failures in virtualized environments
+    sysctl -p/etc/sysctl.d/99-scylla-sched.conf || :
 fi
 
 #DEBHELPER#