Typo fix: fetchting -> fetching

Author: Andrew Ash <andrew@andrewash.com>

Closes #680 from ash211/patch-3 and squashes the following commits:

9ce3746 [Andrew Ash] Typo fix: fetchting -> fetching

make-distribution.sh

@@ -189,7 +189,7 @@ if [ "$SPARK_TACHYON" == "true" ]; then
   TMPD=`mktemp -d 2>/dev/null || mktemp -d -t 'disttmp'`
 
   pushd $TMPD > /dev/null
-  echo "Fetchting tachyon tgz"
+  echo "Fetching tachyon tgz"
   wget "$TACHYON_URL"
 
   tar xf "tachyon-${TACHYON_VERSION}-bin.tar.gz"