build_release.py: making sure we're also compressing the released images

Signed-off-by: Ricardo Salveti de Araujo <ricardo.salveti@linaro.org>
diff --git a/build_release.py b/build_release.py
index 74cb71e..fa81975 100755
--- a/build_release.py
+++ b/build_release.py
@@ -23,7 +23,7 @@
 
 from linaro_fetch_image import fetch_image
 
-from build_images import build_image
+from build_images import build_image, compress_image
 
 import argparse
 import os
@@ -71,6 +71,7 @@
         hwpf = dm.download(url, None)
         imgfile = get_image_name(odir,url,args.binary_type)
         build_image(lmc, imgfile, hwpack, hwpf, args.binary_type, rfsf)
+        compress_image(imgfile)
 
 if __name__ == '__main__':
     main()