mention what happens if OPENSSL_NO_RC2 is defined

Reviewed-by: NTomas Mraz <tmraz@fedoraproject.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9415)

(cherry picked from commit 8c47e55ee69500e31e80458682c6e022294cd0be)

doc/man1/pkcs12.pod

@@ -225,7 +225,8 @@ for this search. If the search fails it is considered a fatal error.
 
 Encrypt the certificate using triple DES, this may render the PKCS#12
 file unreadable by some "export grade" software. By default the private
-key is encrypted using triple DES and the certificate using 40 bit RC2.
+key is encrypted using triple DES and the certificate using 40 bit RC2
+unless RC2 is disabled in which case triple DES is used.
 
 =item B<-keypbe alg>, B<-certpbe alg>