iteritems() was dropped in recent Python3 releases and items() is compatible
with Python 2.7.

Change-Id: If76a9d1aa3d23f3c38ec2135b42d63f64c4b1332

Change-Id: I556ab82a1dc0ce711958404165e419275ff5ce19

Change-Id: I9967f867b8695e4a5bc4759ca81eebe5ef2309c1

Change-Id: I93e135a9366c1f7c93397dfa0c342428fb64eb1c

Change-Id: Ib4cb70615af8da2f1037b0a43520c215365979ba

"names" makes a separate call to the package management frontend to
install each package, whereas "pkgs" makes just a single call so that it
improves performance.