[SPARK-5188][BUILD] make-distribution.sh should support curl, not only wget to get Tachyon

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

1 files changed, 2 insertions, 2 deletions

diff --git a/build/mvn b/build/mvn
index f91e2b4bdc..a87c5a2623 100755
--- a/build/mvn
+++ b/build/mvn
@@ -48,11 +48,11 @@ install_app() {
     # check if we already have the tarball
     # check if we have curl installed
     # download application
-    [ ! -f "${local_tarball}" ] && [ -n "`which curl 2>/dev/null`" ] && \
+    [ ! -f "${local_tarball}" ] && [ $(command -v curl) ] && \
       echo "exec: curl ${curl_opts} ${remote_tarball}" && \
       curl ${curl_opts} "${remote_tarball}" > "${local_tarball}"
     # if the file still doesn't exist, lets try `wget` and cross our fingers
-    [ ! -f "${local_tarball}" ] && [ -n "`which wget 2>/dev/null`" ] && \
+    [ ! -f "${local_tarball}" ] && [ $(command -v wget) ] && \
       echo "exec: wget ${wget_opts} ${remote_tarball}" && \
       wget ${wget_opts} -O "${local_tarball}" "${remote_tarball}"
     # if both were unsuccessful, exit