Remove duplicate Gerrit-ApiType

The Gerrit-ApiType is already defined in the gerit_plugin() rule: [1].

[1] https://gerrit.googlesource.com/gerrit/+/master/tools/bzl/plugin.bzl#42

Change-Id: Ib1191febc4139f60b12cdcb64eb35abf24501f52

BUILD

diff --git a/BUILD b/BUILD
index b9db44e..2d4dd7d 100644
--- a/BUILD
+++ b/BUILD
@@ -6,7 +6,6 @@
     resources = glob(["src/main/resources/**/*"]),
     manifest_entries = [
         "Gerrit-PluginName: reviewers-by-blame",
-        "Gerrit-ApiType: plugin",
         "Gerrit-Module: com.googlesource.gerrit.plugins.reviewersbyblame.ReviewersByBlameModule",
         "Implementation-Title: Reviewers By Blame",
         "Implementation-URL: https://gerrit.googlesource.com/plugins/reviewers-by-blame",