RT2518: fix pod2man errors

pod2man now complains when item tags are not sequential.
Also complains about missing =back and other tags.
Silence the warnings; most were already done.
Reviewed-by: NTim Hudson <tjh@openssl.org>

doc/ssl/SSL_CTX_use_psk_identity_hint.pod

@@ -83,7 +83,12 @@ Return values from the server callback are interpreted as follows:
 
 =over 4
 
-=item > 0
+=item Z<>0
+
+PSK identity was not found. An "unknown_psk_identity" alert message
+will be sent and the connection setup fails.
+
+=item E<gt>0
 
 PSK identity was found and the server callback has provided the PSK
 successfully in parameter B<psk>. Return value is the length of
@@ -96,11 +101,6 @@ data to B<psk> and return the length of the random data, so the
 connection will fail with decryption_error before it will be finished
 completely.
 
-=item Z<>0
-
-PSK identity was not found. An "unknown_psk_identity" alert message
-will be sent and the connection setup fails.
-
 =back
 
 =cut

doc/ssl/SSL_shutdown.pod

@@ -104,7 +104,7 @@ erroneous SSL_ERROR_SYSCALL may be flagged even though no error occurred.
 The shutdown was successfully completed. The "close notify" alert was sent
 and the peer's "close notify" alert was received.
 
-=item -1
+=item E<lt>0
 
 The shutdown was not successful because a fatal error occurred either
 at the protocol level or a connection failure occurred. It can also occur if