Replaced all internal usage of sha.h.

ChangeLog

dsa.h

examples/nettle-benchmark.c

hmac.h

rsa.h

sha-example.c

sha1-compress.c

sha1-meta.c

sha1.c

sha224-meta.c

sha256-compress.c

sha256-meta.c

sha256.c

sha384-meta.c

sha512-compress.c

sha512-meta.c

sha512.c

testsuite/pbkdf2-test.c

testsuite/sha1-huge-test.c

testsuite/sha1-test.c