socket: set SO_REUSEADDR when binding sockets
socket: set SO_REUSEADDR when binding sockets

Without this, I found that if i killed my tablet server process,
I couldn't restart it for a while due to the lingering socket.
Seems like a good thing to set by default so servers can be
quickly restarted after a kill -9

Change-Id: Ifa3f5b14bb3f732455700311354525bbcb372ef0
Reviewed-on: http://gerrit.ent.cloudera.com:8080/183
Tested-by: jenkins <c14f3aae4f03a600341a3b92ec1ffaac2338cde0@cloudera.com>
Reviewed-by: Matteo Bertozzi <1d5ca967930bde0bdce795acbf71a5e281d2d4e5@cloudera.com>

EvilMcJerkface/kudu,helifu/kudu,helifu/kudu,EvilMcJerkface/kudu,helifu/kudu,andrwng/kudu,cloudera/kudu,cloudera/kudu,cloudera/kudu,andrwng/kudu,helifu/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,InspurUSA/kudu,andrwng/kudu,EvilMcJerkface/kudu,EvilMcJerkface/kudu,cloudera/kudu,andrwng/kudu,InspurUSA/kudu,cloudera/kudu,andrwng/kudu,InspurUSA/kudu,EvilMcJerkface/kudu,helifu/kudu,InspurUSA/kudu,andrwng/kudu,cloudera/kudu,cloudera/kudu,EvilMcJerkface/kudu,EvilMcJerkface/kudu,andrwng/kudu,helifu/kudu,InspurUSA/kudu,helifu/kudu,InspurUSA/kudu,andrwng/kudu,EvilMcJerkface/kudu,cloudera/kudu,andrwng/kudu,helifu/kudu,InspurUSA/kudu,cloudera/kudu,helifu/kudu,InspurUSA/kudu