Remove 'main' directory from src/keepanno

Change-Id: I964cec8d5bc6ff4b0a8cef62296c3a126c04be44
diff --git a/build.gradle b/build.gradle
index 8dbce66..f775822 100644
--- a/build.gradle
+++ b/build.gradle
@@ -200,7 +200,7 @@
     }
     keepanno {
         java {
-            srcDirs = ['src/keepanno/main/java']
+            srcDirs = ['src/keepanno/java']
         }
     }
 }