FLUME-1337: Add IDEA files to .gitignore
FLUME-1337: Add IDEA files to .gitignore

(Mike Percy via Brock Noland)

tinawenqiao/flume,szaboferee/flume,tinawenqiao/flume,tmgstevens/flume,szaboferee/flume,szaboferee/flume,tinawenqiao/flume,tmgstevens/flume,iaiengxia/flume,iaiengxia/flume,tmgstevens/flume,iaiengxia/flume,szaboferee/flume,tinawenqiao/flume,tmgstevens/flume,iaiengxia/flume