Document -trusted_first option in man pages and help.

Add -trusted_first description to help messages and man pages
of tools that deal with certificate verification.
diff --git a/apps/cms.c b/apps/cms.c
index ddc3d5e..bb85a20 100644
--- a/apps/cms.c
+++ b/apps/cms.c
@@ -716,6 +716,7 @@
 		BIO_printf (bio_err, "-text          include or delete text MIME headers\n");
 		BIO_printf (bio_err, "-CApath dir    trusted certificates directory\n");
 		BIO_printf (bio_err, "-CAfile file   trusted certificates file\n");
+		BIO_printf (bio_err, "-trusted_first use locally trusted certificates first when building trust chain\n");
 		BIO_printf (bio_err, "-crl_check     check revocation status of signer's certificate using CRLs\n");
 		BIO_printf (bio_err, "-crl_check_all check revocation status of signer's certificate chain using CRLs\n");
 #ifndef OPENSSL_NO_ENGINE