fix regression from PR #221

when bootstrapping into empty directory with -Dappbase=... the version from the fetched getdown.txt must be extracted before calling processArg(SysProps.overrideAppbase(_appbase)) - otherwise _version is -1 instead of the version provided in the just downloaded getdown.txt.

core/src/main/java/com/threerings/getdown/data/Application.java

@@ -579,6 +579,9 @@ public class Application
             config = new Config(cdata);
         }
 
+        // extract our version information
+        _version = config.getLong("version", -1L);
+
         // first determine our application base, this way if anything goes wrong later in the
         // process, our caller can use the appbase to download a new configuration file
         _appbase = config.getString("appbase");
@@ -594,9 +597,6 @@ public class Application
             _appbase = _appbase + "/";
         }
 
-        // extract our version information
-        _version = config.getLong("version", -1L);
-
         // if we are a versioned deployment, create a versioned appbase
         try {
             _vappbase = createVAppBase(_version);