adding dateutil to the image, as i do not know why RDEPENDS does not ensure...

adding dateutil to the image, as i do not know why RDEPENDS does not ensure that dateutil exists in the rootfs

recipes-core/images/core-image-ros.bb

@@ -27,4 +27,4 @@ ROOTFS_POSTPROCESS_COMMAND += "remove_packaging_data_files ; augment_hosts_setti
 IMAGE_INSTALL += "packagegroup-core-ssh-openssh git cmake \
   boost boost-dev log4cxx log4cxx-dev libbz2-dev \
   python-modules python-empy python-pyyaml python-nose \
-  python-setuptools python-rospkg python-vcstools python-rosinstall"
+  python-setuptools python-rospkg python-dateutil python-vcstools python-rosinstall"