Fix building when OpenSSL was compiled -nossl2 or -noss3

This also fixes building with LibreSSL 2.2 (no SSLv2) and 2.3 (no SSLv3)

src/httperf.c

@@ -664,10 +664,14 @@ main(int argc, char **argv)
                         {
                             if (strcasecmp (optarg, "auto") == 0)
                                 param.ssl_protocol = 0;
+#ifndef OPENSSL_NO_SSL2
                             else if (strcasecmp (optarg, "SSLv2") == 0)
                                 param.ssl_protocol = 2;
+#endif
+#ifndef OPENSSL_NO_SSL3
                             else if (strcasecmp (optarg, "SSLv3") == 0)
                                 param.ssl_protocol = 3;
+#endif
                             else if (strcasecmp (optarg, "TLSv1") == 0)
                                 param.ssl_protocol = 4;
                             else
@@ -997,10 +1001,14 @@ main(int argc, char **argv)
                 {
                     /* 0/auto for SSLv23 */
                     case 0: ssl_ctx = SSL_CTX_new (SSLv23_client_method ()); break;
+#ifndef OPENSSL_NO_SSL2
                     /* 2/SSLv2 */
                     case 2: ssl_ctx = SSL_CTX_new (SSLv2_client_method ()); break;
+#endif
+#ifndef OPENSSL_NO_SSL3
                     /* 3/SSLv3 */
                     case 3: ssl_ctx = SSL_CTX_new (SSLv3_client_method ()); break;
+#endif
                     /* 4/TLSv1 */
                     case 4: ssl_ctx = SSL_CTX_new (TLSv1_client_method ()); break;
                 }
@@ -1204,8 +1212,12 @@ main(int argc, char **argv)
         switch (param.ssl_protocol)
         {
             case 0: printf (" --ssl-protocol=auto");  break;
+#ifndef OPENSSL_NO_SSL2
             case 2: printf (" --ssl-protocol=SSLv2"); break;
+#endif
+#ifndef OPENSSL_NO_SSL3
             case 3: printf (" --ssl-protocol=SSLv3"); break;
+#endif
             case 4: printf (" --ssl-protocol=TLSv1"); break;
         }
 #endif