fix connection error message

it/src/test/java/com/sonar/runner/it/JavaTest.java

     // expect build failure
     assertThat(result.getStatus()).isNotEqualTo(0);
     // with the following message
-    assertThat(result.getLogs()).contains("ERROR: Sonar server 'http://foo' can not be reached");
+    assertThat(result.getLogs()).contains("server 'http://foo' can not be reached");
   }
 
   // SONARPLUGINS-3574

sonar-runner-api/src/main/java/org/sonar/runner/impl/ServerConnection.java

 
 class ServerConnection {
 
-  private static final String SONAR_SERVER_CAN_NOT_BE_REACHED = "Sonar server ''{0}'' can not be reached";
+  private static final String SONAR_SERVER_CAN_NOT_BE_REACHED = "SonarQube server ''{0}'' can not be reached";
   private static final String STATUS_RETURNED_BY_URL_IS_INVALID = "Status returned by url : ''{0}'' is invalid : {1}";
   static final int CONNECT_TIMEOUT_MILLISECONDS = 5000;
   static final int READ_TIMEOUT_MILLISECONDS = 60000;