scripts: python3: convert iterables to lists

Converted return value of items() keys() and values() to
lists when dictionary is modified in the loop and when
the result is added to the list.

(From OE-Core rev: 874a269eb1d70060c2f3b3f8b70800e2aea789f4)

Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/combo-layer

@@ -1186,7 +1186,7 @@ def update_with_history(conf, components, revisions, repos):
         msg = conf_commit_msg(conf, components)
         new_tree = runcmd("git write-tree", **wargs).strip()
         new_rev = runcmd("git commit-tree".split() +
-                         add_p([head] + additional_heads.keys()) +
+                         add_p([head] + list(additional_heads.keys())) +
                          ["-m", msg, new_tree],
                          **wargs).strip()
         # And done! This is the first time we change the HEAD in the actual work tree.