isset function was moved to config file related functions by accident,
this change also simplfies the isset in a bash >=4.2 way.
All supported distro has at least bash 4.2. (RHEL6 used 4.1)
Change-Id: Id644b46ff9cdbe18cde46e96aa72764e1c8653ac
* config/INI functions from functions-common to to inc/ini-config
* local.conf meta-config functions from lib/config to inc/meta-config
Change-Id: I00fab724075a693529273878875cfd292d00b18a