A few short fixes to splitting/iteration done over package lists
in license.bbclass, package_manager.py and rootfs.py.
[YOCTO #7664]
(From OE-Core rev: a902e98c5938f52ec960e0518e0ceaf8f5ee610c)
Signed-off-by: Alex Franco <alejandro.franco@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>