Pull cord-tester images from dockerhub as they are available now on dockerhub.
Change image names to be compatible with dockerhub image names.
Update prerequisites.sh last step to pull all the cord-tester docker images.
This should make the cord-test.py build all step redundant now since images should be available for testing immediately after prerequisites.sh are run.

Change-Id: I64cf664a214924349d6728ca2a52974decdef47f
diff --git a/src/test/utils/CordContainer.py b/src/test/utils/CordContainer.py
index cd31827..6ab5363 100644
--- a/src/test/utils/CordContainer.py
+++ b/src/test/utils/CordContainer.py
@@ -832,7 +832,7 @@
     host_guest_map = ( (host_db_dir, guest_db_dir),
                        (host_config_dir, guest_config_dir)
                        )
-    IMAGE = 'cord-test/radius'
+    IMAGE = 'cordtest/radius'
     NAME = 'cord-radius'
 
     def __init__(self, name = NAME, image = IMAGE, prefix = '', tag = 'candidate',
@@ -881,7 +881,7 @@
     guest_quagga_config = '/root/config'
     quagga_config_file = os.path.join(guest_quagga_config, 'testrib.conf')
     host_guest_map = ( (host_quagga_config, guest_quagga_config), )
-    IMAGE = 'cord-test/quagga'
+    IMAGE = 'cordtest/quagga'
     NAME = 'cord-quagga'
 
     def __init__(self, name = NAME, image = IMAGE, prefix = '', tag = 'candidate',