master: fix missing dependency between master_proto and krpc
master: fix missing dependency between master_proto and krpc

master_proto has KRPC-generated sources in it, so it needs to depend on the
krpc library. I saw a build failure on a gerrit build because of this --
probably only occurs occasionally when CMake decides to build in a different
order.

Change-Id: I9a977350a2a8877057b468c462af054c4f48ea73
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/6248
Reviewed-by: Jean-Daniel Cryans <4bf4c125525b8623ac45dfd7774cbf531df19085@cloudera.com>
Tested-by: jenkins

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