SPARK-2241: quote command line args in ec2 script

To preserve quoted command line args (in case options have space in them).

Author: Ori Kremer <ori.kremer@gmail.com>

Closes #1169 from orikremer/quote_cmd_line_args and squashes the following commits:

67e2aa1 [Ori Kremer] quote command line args

ec2/spark-ec2

@@ -19,4 +19,4 @@
 #
 
 cd "`dirname $0`"
-PYTHONPATH="./third_party/boto-2.4.1.zip/boto-2.4.1:$PYTHONPATH" python ./spark_ec2.py $@
+PYTHONPATH="./third_party/boto-2.4.1.zip/boto-2.4.1:$PYTHONPATH" python ./spark_ec2.py "$@"