collect data for user membase, not northscale

Change-Id: I221579057ea0b8f8af63156cc3425136f5cb46a2
Reviewed-on: http://review.membase.org/3261
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Sean Lynch <seanl@literati.org>

collect_info

@@ -167,8 +167,8 @@ _tasks = [
     UnixTask("System activity reporter", "sar 1 10"),
     UnixTask("System paging activity", "vmstat 1 10"),
     UnixTask("System uptime", "uptime"),
-    UnixTask("northscale user definition", "getent passwd northscale"),
-    UnixTask("northscale user limits", "su northscale -c \"ulimit -a\"",
+    UnixTask("membase user definition", "getent passwd membase"),
+    UnixTask("membase user limits", "su membase -c \"ulimit -a\"",
          privileged=True),
     UnixTask("Interrupt status", "intrstat 1 10"),
     UnixTask("Processor status", "mpstat 1 10"),