gpg-error-config: Don't use local variables.

* src/gpg-error-config-new.in: Use global variables only.

Since Korn Shell requires different syntax for function to declare
local variables, and some OS use Korn Shell as /bin/sh, avoid
non-portable use of "local".

• Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>