Remove obsolete key formats.

Remove support for RSA_NET and Netscape key format (-keyform n).

Also removed documentation of SGC.

Reviewed-by: Viktor Dukhovni <viktor@openssl.org>

apps/opt.c

diff --git a/apps/opt.c b/apps/opt.c
index b81cec4..bfb039e 100644
--- a/apps/opt.c
+++ b/apps/opt.c
@@ -256,15 +256,11 @@
         break;
     case 'N':
     case 'n':
-        if (strcmp(s, "NSS") == 0 || strcmp(s, "nss") == 0) {
-            if ((flags & OPT_FMT_NSS) == 0)
-                return opt_format_error(s, flags);
-            *result = FORMAT_NSS;
-        } else {
-            if ((flags & OPT_FMT_NETSCAPE) == 0)
-                return opt_format_error(s, flags);
-            *result = FORMAT_NETSCAPE;
-        }
+        if ((flags & OPT_FMT_NSS) == 0)
+            return opt_format_error(s, flags);
+        if (strcmp(s, "NSS") != 0 && strcmp(s, "nss") != 0)
+            return opt_format_error(s, flags);
+        *result = FORMAT_NSS;
         break;
     case 'S':
     case 's':