Don't generate or require removed.txt file, fix initial API generation

Removes all existing removed.txt files. Fixes API generation for
annotations project. Fixes the build.

Test: ./gradlew updateApi
Change-Id: Idf8320c5bd5bfe71bc6302af77513c9947b49a70
diff --git a/annotations/build.gradle b/annotations/build.gradle
index 195a0e7..b8a14b7 100644
--- a/annotations/build.gradle
+++ b/annotations/build.gradle
@@ -64,7 +64,9 @@
 // Disable strict javadoc lint checks with javadoc v8 builds on Mac. http://b/26744780
 if (JavaVersion.current().isJava8Compatible()) {
     tasks.withType(Javadoc) {
-        options.addBooleanOption('Xdoclint:none', true)
+        if (options.doclet == null) {
+            options.addBooleanOption('Xdoclint:none', true)
+        }
     }
 }