Put use_init_interp in $nl_flags as either .true. or .false. so can be correctly handled in namelist_defaults_ctsm.xml

Logical attributes in namelist_defaults files need to have been converted to the $nl_flags dictionary so that they will be either .true. or .false. so that the comparison works correctly. Logical values are allowed to be different case, and shortened with or without the "." in front and after. As such they should be stored in $nl_flags in the two options, based on the logical value.

use_init_interp isn't handled this way, and as such if the user enters "T" or "TRUE" the namelist_defaults matches might not work correctly.