Use ubuntu instead of the distribution codename

Signed-off-by: Fathi Boudra <fathi.boudra@linaro.org>
diff --git a/build_images.py b/build_images.py
index 1d344ed..3a3a6d1 100755
--- a/build_images.py
+++ b/build_images.py
@@ -295,8 +295,8 @@
     p.add_argument('-b', dest='binaries', action='append',
                    help='The binaries to generate for, default=%s' %
                    ', '.join(binaries))
-    p.add_argument('-p', dest='platform', default='raring',
-                   help='The platform, default=raring')
+    p.add_argument('-p', dest='platform', default='ubuntu',
+                   help='The platform, default=ubuntu')
     p.add_argument('-pw', dest='platform_hwpack', default=False,
                    help='The platform for hwpack, default - same as platform')
     p.add_argument('-o', dest='out_dir', default='./out',
diff --git a/crawler.py b/crawler.py
index 924ba2b..edb7270 100755
--- a/crawler.py
+++ b/crawler.py
@@ -96,4 +96,4 @@
             print "  %s: %s" % hwpack
 
     print "latest nano:"
-    print "  %s %s" % latest_rfs('http://snapshots.linaro.org/raring/images/nano')
+    print "  %s %s" % latest_rfs('http://snapshots.linaro.org/ubuntu/images/nano')