More accurate doc of -ssl_config option

Reviewed-by: NMatthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
Reviewed-by: NDmitry Belyavskiy <beldmit@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/10972)

apps/s_client.c

@@ -614,7 +614,7 @@ const OPTIONS s_client_options[] = {
     {"ssl_client_engine", OPT_SSL_CLIENT_ENGINE, 's',
      "Specify engine to be used for client certificate operations"},
 #endif
-    {"ssl_config", OPT_SSL_CONFIG, 's', "Use specified configuration file"},
+    {"ssl_config", OPT_SSL_CONFIG, 's', "Use specified section for SSL_CTX configuration"},
 #ifndef OPENSSL_NO_CT
     {"ct", OPT_CT, '-', "Request and parse SCTs (also enables OCSP stapling)"},
     {"noct", OPT_NOCT, '-', "Do not request or parse SCTs (default)"},

doc/man1/openssl-s_client.pod.in

@@ -9,7 +9,7 @@ openssl-s_client - SSL/TLS client program
 
 B<openssl> B<s_client>
 [B<-help>]
-[B<-ssl_config> I<file>]
+[B<-ssl_config> I<section>]
 [B<-connect> I<host:port>]
 [B<-host> I<hostname>]
 [B<-port> I<port>]
@@ -154,9 +154,9 @@ manual page.
 
 Print out a usage message.
 
-=item B<-ssl_config> I<filename>
+=item B<-ssl_config> I<section>
 
-Use the specified configuration file.
+Use the specified section of the configuration file to configure the B<SSL_CTX> object.
 
 =item B<-connect> I<host>:I<port>