statedump: Print curr_stdalloc in mempool statedump ...

...for, it is curr_stdalloc that is incremented for every mem_get()
and decremented on every call to mem_put() and can be used to detect
leaks, when cold_count is 0.

        Backport of: http://review.gluster.org/8557

Change-Id: I1f4aac3af1234b9a76be7cb86ef26d728788950c
BUG: 1136831
Signed-off-by: Krutika Dhananjay <kdhananj@redhat.com>
Reviewed-on: http://review.gluster.org/8705
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>