gpg: Disable keydb handle caching only for W32
* g10/getkey.c (getkey_end) [!W32]: Re-enable caching.
This change limits of the effects of commit
d3d640b9cc98dd0d06b49a2e4d46eb67af96fe29 to W32 system.
- GnuPG-bug-id: T3097
- Signed-off-by: Werner Koch <wk@gnupg.org>