Make the documentation correct for concurrent default

This corresponds to the default set at https://github.com/JoeDog/siege/blob/master/doc/siegerc.in#L267

Author: jkburges

INSTALL

@@ -167,7 +167,8 @@ If that is the case, then follow the steps in item #1 below...
     -q, --quiet               QUIET turns verbose off and suppresses output.
     -g, --get                 GET, pull down HTTP headers and display the
                               transaction. Great for application debugging.
-    -c, --concurrent=NUM      CONCURRENT users, default is 10
+    -c, --concurrent=NUM      CONCURRENT users, default is 25 or whatever is
+                              specified in ~/.siegerc.
     -r, --reps=NUM            REPS, number of times to run the test.
     -t, --time=NUMm           TIMED testing where "m" is modifier S, M, or H
                               ex: --time=1H, one hour test.

src/main.c

@@ -142,7 +142,8 @@ display_help()
   puts("  -g, --get                 GET, pull down HTTP headers and display the");
   puts("                            transaction. Great for application debugging.");
   puts("  -p, --print               PRINT, like GET only it prints the entire page.");
-  puts("  -c, --concurrent=NUM      CONCURRENT users, default is 10");
+  puts("  -c, --concurrent=NUM      CONCURRENT users, default is default is 25 or");
+  puts("                              whatever is specified in ~/.siegerc");
   puts("  -r, --reps=NUM            REPS, number of times to run the test." );
   puts("  -t, --time=NUMm           TIMED testing where \"m\" is modifier S, M, or H");
   puts("                            ex: --time=1H, one hour test." );