[SPARK-3566] [BUILD] .gitignore and .rat-excludes should consider Windows cmd...

[SPARK-3566] [BUILD] .gitignore and .rat-excludes should consider Windows cmd file and Emacs' backup files

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

Closes #2426 from sarutak/emacs-metafiles-ignore and squashes the following commits:

a306020 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into emacs-metafiles-ignore
6a0a5eb [Kousuke Saruta] Added cmd file entry to .rat-excludes and .gitignore
897da63 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into emacs-metafiles-ignore
8cade06 [Kousuke Saruta] Modified .gitignore to ignore emacs lock file and backup file

.gitignore

 *~
+*.#*
+*#*#
 *.swp
 *.ipr
 *.iml
@@ -16,6 +18,7 @@ third_party/libmesos.so
 third_party/libmesos.dylib
 conf/java-opts
 conf/*.sh
+conf/*.cmd
 conf/*.properties
 conf/*.conf
 conf/*.xml

.rat-excludes

@@ -20,6 +20,7 @@ log4j.properties.template
 metrics.properties.template
 slaves
 spark-env.sh
+spark-env.cmd
 spark-env.sh.template
 log4j-defaults.properties
 bootstrap-tooltip.js