lib/dstat: Include page stats

Add -g option for dstat.

From the man page:

       -g, --page
              enable page stats (page in, page out)

Change-Id: I865304483af0a529ea8722ed0a9f35ab350670d2
diff --git a/lib/dstat b/lib/dstat
index a2c522c..3852652 100644
--- a/lib/dstat
+++ b/lib/dstat
@@ -24,7 +24,7 @@
 # start_dstat() - Start running processes, including screen
 function start_dstat {
     # A better kind of sysstat, with the top process per time slice
-    DSTAT_OPTS="-tcmndrylp --top-cpu-adv"
+    DSTAT_OPTS="-tcmndrylpg --top-cpu-adv"
     if [[ -n ${SCREEN_LOGDIR} ]]; then
         screen_it dstat "cd $TOP_DIR; dstat $DSTAT_OPTS | tee $SCREEN_LOGDIR/$DSTAT_FILE"
     else