Description: Revert "Fix Linux savegame path issue" from Alexander Olofsson <ace@haxalot.com>

Upstream's d11404a6e9ddf5017f18b2ab0565c19e066f33ee

Given the buster freeze, don't break this for buster users just now.

--- a/src/common/system/system_linux.cpp
+++ b/src/common/system/system_linux.cpp
@@ -90,8 +90,8 @@ std::string CSystemUtilsLinux::GetSaveDi
 #else
     std::string savegameDir;
 
-    // Determine savegame dir according to XDG Base Directory Specification
-    auto envXDG_DATA_HOME = GetEnvVar("XDG_DATA_HOME");
+    // Determine savegame dir according to XDG Base Directory Specification; with a Debian-specific historic deviation
+    auto envXDG_DATA_HOME = GetEnvVar("XDG_CONFIG_DATA");
     if (envXDG_DATA_HOME.empty())
     {
         auto envHOME = GetEnvVar("HOME");