Merge branch 'gc/config-parsing-cleanup'

Config API clean-up to reduce its dependence on static variables

* gc/config-parsing-cleanup:
  config.c: rename "struct config_source cf"
  config: report cached filenames in die_bad_number()
  config.c: remove current_parsing_scope
  config.c: remove current_config_kvi
  config.c: plumb the_reader through callbacks
  config.c: create config_reader and the_reader
  config.c: don't assign to "cf_global" directly
  config.c: plumb config_source through static fns

Author: gitster