Fix bug with wrong bool opt value interpolation

Other way of global debug opt value interpolation is needed
for the pecan_debug option, as bool opt interpolation
seems to be not working in the oslo.config

Closes-Bug: 1373360
Change-Id: I77c4d02b0821b559d7de7329acf11c6d490f51b1
Merge "Fix bug with wrong bool opt value interpolation"