(SHA1_DATA_LENGTH): Deleted unused macro.

(sha1_init): Use memcpy to initialize the state vector.
(SHA1_INCR): Deleted macro.
(sha1_update): Use MD_UPDATE macro, to reduce code duplication.
(sha1_digest): Use MD_FINAL macro.
(sha1_final): Deleted function.

Rev: nettle/sha1.c:1.3