Android: Change the file browser dialog ok button title

I hope this will make it more clear to users that they are suppose to
select the dircetory that has the games.

Source/Android/app/src/main/res/values/strings.xml

@@ -299,4 +299,6 @@
 
     <!-- Extra Leanback Homescreen Channels-->
     <string name="homescreen_favorites">Favorites</string>
+
+    <string name="select_dir">Select This Directory</string>
 </resources>