protocol/server: Initialize connection variable

Change-Id: I46badd812e9b936911ddd2793cef7ce30ec220a6
BUG: 979237
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/5266
Reviewed-by: Raghavendra G <rgowdapp@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>