We have shell scripts and Windows batch files, so we should enforce proper EOL character.

Author: Kousuke Saruta <sarutak@oss.nttdata.co.jp>

Closes #2726 from sarutak/eol-enforcement and squashes the following commits:

9748c3f [Kousuke Saruta] Fixed make.bat
252de89 [Kousuke Saruta] Removed extra characters from make.bat
5b81c00 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into eol-enforcement
8633ed2 [Kousuke Saruta] merge branch 'master' of git://git.apache.org/spark into eol-enforcement
5d630d8 [Kousuke Saruta] Merged
ba10797 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into eol-enforcement
7407515 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into eol-enforcement
772fd4e [Kousuke Saruta] Normized EOL character in make.bat and compute-classpath.cmd
ac7f873 [Kousuke Saruta] Added an entry for .gitattributes to .rat-excludes
1570e77 [Kousuke Saruta] Added .gitattributes