HADOOP-4571. Updating git ignore file also.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/core/trunk@713853 13f79535-47bb-0310-9956-ffa450edef68

.gitignore

@@ -28,4 +28,7 @@ docs/api/
 logs/
 src/contrib/ec2/bin/hadoop-ec2-env.sh
 src/contrib/index/conf/index-config.xml
-src/docs/build
+src/contrib/chukwa/conf/alert.conf
+src/contrib/chukwa/conf/chukwa-slaves
+src/contrib/chukwa/conf/initial_adaptors
+src/docs/build