random: Symbol name cleanup for random-drbg.c.
* random/random-drbg.c: Rename all static objects and macros from "gcry_drbg" to "drbg". (drbg_string_t): New typedef. (drbg_gen_t): New typedef. (drbg_state_t): New typedef. Replace all "struct drbg_state_s *" by this. (_drbg_init_internal): Replace xcalloc_secure by xtrycalloc_secure so that an error if actually returned. (gcry_rngdrbg_cavs_test): Ditto. (gcry_drbg_healthcheck_sanity): Ditto.
- Signed-off-by: Werner Koch <wk@gnupg.org>