Improve ovs_deploy.bash script

Improve ovs_deploy.bash script

Improved ovs_deploy.bash script [1]:
- Check if there is an error during the execution.
- Removed "prerequisites" function because is not called.
- Modified DPDK package installation: execute "make config" and then "make"
- Added comments.

[1]https://github.com/opnfv/yardstick/blob/master/yardstick/resources/scripts/install/ovs_deploy.bash

JIRA: YARDSTICK-916

Change-Id: I3029f983dde72aa46f6fdd61dd64d086ab3c2af6
Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>