Use GET for Keystone health check

Some WSGI implementations may not support HEAD, resulting in a
false negative for the health check. GET will give an accurate
result in these cases.

Change-Id: I0fa0ecbeac64525d9108bfa618ac1afa7dcaa2a3
Depends-On: I22686d05670fc6c947611f8044dea498239a4212

server/healthcheck/index.js

@@ -44,7 +44,7 @@ module.exports = function healthcheck(plugin, server) {
       const req = request({
         hostname: getHostname(),
         port    : getPort(),
-        method  : 'HEAD'
+        method  : 'GET'
       }, (res)=> {
         const statusCode = res.statusCode;
         if (statusCode >= 400) {