glib: Rename variable to make it more clear what it is

also fixes shadow warning
6 jobs for fix_more_shadows in 5 minutes and 14 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
passed #374863
build

00:03:11

passed #374868
build_android

00:01:00

passed #374864
build_clang_libcpp

00:03:14

passed #374867
build_clazy

00:05:13

passed #374866
build_mingw64_fedora

00:02:31

passed #374865
build_ubuntu_16_04

00:01:40