Use "if dict.get(key):" instead "if key in dict and dict[key]:"

Use "if dict.get(key):" instead "if key in dict and dict[key]:"

Use "if dict.get(key):" instead of "if key in dict and dict[key]:"
which makes code more clear and intelligible. Note this patch doesn't
change judging conditions, all "is not None" are retained.

Change-Id: Ieed57a21eb4b08c6f9a25b180a3625154a0d5fde