speedtest: --serverid for backwards compatibility.

Accept it, but ignore it.

Change-Id: Ifa302e2d3e397b169f4bfa6139ec313a7ed8e0c1
diff --git a/speedtest/options.cc b/speedtest/options.cc
index f657b0c..7267856 100644
--- a/speedtest/options.cc
+++ b/speedtest/options.cc
@@ -77,6 +77,7 @@
 const int kOptSkipUpload = 1004;
 const int kOptSkipPing = 1005;
 const int kOptNoReportResults = 1006;
+const int kOptServerId = 1007;
 
 const int kOptMinTransferTime = 1100;
 const int kOptMaxTransferTime = 1101;
@@ -121,6 +122,7 @@
     {"ping_timeout", required_argument, nullptr, kOptPingTimeout},
     {"exponential_moving_average", no_argument, nullptr,
         kOptExponentialMovingAverage},
+    {"serverid", required_argument, nullptr, kOptServerId},  // ignored
     {nullptr, 0, nullptr, 0},
 };
 const int kMaxNumber = 1000;
@@ -441,6 +443,9 @@
       case kOptExponentialMovingAverage:
         options->exponential_moving_average = true;
         break;
+      case kOptServerId:
+        // --serverid is accepted but ignored, for backwards compatibility.
+        break;
       default:
         return false;
     }