Add thrift, jflex, yacc files to cscope file list.

I find it useful to have these indexed by cscope.  Also, gitignore
files generated with cscope -q (inverted index).

Change-Id: I8d5bcd34706c40357b94337db4b72dccecdecbd9
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/3910
Reviewed-by: Nong Li <nong@cloudera.com>
Tested-by: Daniel Hecht <dhecht@cloudera.com>