When we use `make-distribution.sh` with `--with-tachyon` option, Tachyon will be downloaded by `wget` command but some systems don't have `wget` by default (MacOS X doesn't have).
Other scripts like build/mvn, build/sbt support not only `wget` but also `curl` so `make-distribution.sh` should support `curl` too.

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

Closes #3988 from sarutak/SPARK-5188 and squashes the following commits:

0f546e0 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into SPARK-5188
010e884 [Kousuke Saruta] Merge branch 'SPARK-5188' of github.com:sarutak/spark into SPARK-5188
163687e [Kousuke Saruta] Fixed a merge conflict
e24e01b [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into SPARK-5188
3daf1f1 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into SPARK-5188
3caa4cb [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into SPARK-5188
7cc8255 [Kousuke Saruta] Fix to use \$MVN instead of mvn
a3e908b [Kousuke Saruta] Fixed style
2db9fbf [Kousuke Saruta] Removed redirection from the logic which checks the existence of commands
1e4c7e0 [Kousuke Saruta] Used "command" command instead of "type" command
83b49b5 [Kousuke Saruta] Modified make-distribution.sh so that we use curl, not only wget to get tachyon