Remove 'v2' from import

Author: eskenny

com/magnite/openrtb/v2/openrtb-xapi.proto

@@ -7,7 +7,7 @@
 
 syntax = "proto2";
 
-import "v2/openrtb.proto";
+import "openrtb.proto";
 option java_outer_classname = "OpenRtbXapi";
 package com.magnite.openrtb.v2;