Fix the Content-Type <meta> tag.
Fix the Content-Type <meta> tag.

Error reported by the W3C HTML validator.

Change-Id: Ifae99f5a9d769bd17dc12e0d5554bc3583727fc6

OpenTSDB/opentsdb.net,manolama/opentsdb.net,OpenTSDB/opentsdb.net,OpenTSDB/opentsdb.net,manolama/opentsdb.net,geoffreyanderson/opentsdb.net,manolama/opentsdb.net,geoffreyanderson/opentsdb.net,geoffreyanderson/opentsdb.net