Fix various missing option help messages ...

Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1585)
diff --git a/apps/crl.c b/apps/crl.c
index 5e0fbe5..06b6e5b 100644
--- a/apps/crl.c
+++ b/apps/crl.c
@@ -41,7 +41,7 @@
     {"fingerprint", OPT_FINGERPRINT, '-', "Print the crl fingerprint"},
     {"crlnumber", OPT_CRLNUMBER, '-', "Print CRL number"},
     {"badsig", OPT_BADSIG, '-', "Corrupt last byte of loaded CRL signature (for test)" },
-    {"gendelta", OPT_GENDELTA, '<'},
+    {"gendelta", OPT_GENDELTA, '<', "Other CRL to compare/diff to the Input one"},
     {"CApath", OPT_CAPATH, '/', "Verify CRL using certificates in dir"},
     {"CAfile", OPT_CAFILE, '<', "Verify CRL using certificates in file name"},
     {"no-CAfile", OPT_NOCAFILE, '-',