Don't add a value for FC_FULLNAME in meta face

FC_FULLNAME is affected by variables and could be different
against it. FC_FULLNAME should be dropped from meta face.

Fixes fontconfig/fontconfig#185
5 jobs for issue/185 in 14 minutes and 9 seconds (queued for 1 minute and 7 seconds)
Status Job ID Name Coverage
  Build
passed #1031807
mingw-build

00:05:12

passed #1031881
shared-build

00:04:47

passed #1031985
static-build

00:04:08

failed #1031805
shared-build

00:08:40

failed #1031806
static-build

00:05:18