Updated doc versions to 7.0.0-alpha1 unreleased

docs/Versions.asciidoc

@@ -1,5 +1,5 @@
-:version:               6.0.0-alpha2
-:major-version:         6.x
+:version:               7.0.0-alpha1
+:major-version:         7.x
 :lucene_version:        7.0.0-SNAPSHOT
 :lucene_version_path:   7_0_0
 :branch:                master
@@ -9,7 +9,7 @@
 release-state can be: released | prerelease | unreleased
 //////////
 
-:release-state:   prerelease
+:release-state:   unreleased
 
 :issue:           https://github.com/elastic/elasticsearch/issues/
 :pull:            https://github.com/elastic/elasticsearch/pull/