Remove support for XP specific config location

Current Git for Windows supports an additional configuration location
for system setting. On contemporary versionws of Windows this is
$PROGRAMDATA/Git/config. But XP does not know about $PRORGRAMDATA so
$ALLUSERSPROFILE/Application Data/Git/config was used.

XP itself is EOL for quite some time and Git for Windows ceased to
support it officially with version 2.10.0 (release 3 Sep 2016).

https://github.com/git-for-windows/git/wiki/FAQ#which-versions-of-windows-are-supported
https://git-for-windows.github.io/requirements.html

Signed-off-by: Andreas Heiduk <[email protected]>

Author: asheiduk

Documentation/git-config.txt

@@ -258,8 +258,7 @@ config file (located at `$PROGRAMDATA/Git/config`), intended to contain
 settings for *all* Git-related software running on the machine. Consequently,
 this config file takes an even lower precedence than the
 `$(prefix)/etc/gitconfig` file. Typically `$PROGRAMDATA` points to
-`C:\ProgramData` (on Windows XP the equivalent in `$ALLUSERSPROFILE` is used,
-i.e. `C:\Documents and Settings\All Users\Application Data\Git\config`).
+`C:\ProgramData`.
 
 If no further options are given, all reading options will read all of these
 files that are available. If the global or the system-wide configuration

compat/mingw.c

@@ -3270,13 +3270,8 @@ const char *program_data_config(void)
 
 	if (!initialized) {
 		const char *env = mingw_getenv("PROGRAMDATA");
-		const char *extra = "";
-		if (!env) {
-			env = mingw_getenv("ALLUSERSPROFILE");
-			extra = "/Application Data";
-		}
 		if (env)
-			strbuf_addf(&path, "%s%s/Git/config", env, extra);
+			strbuf_addf(&path, "%s/Git/config", env);
 		initialized = 1;
 	}
 	return *path.buf ? path.buf : NULL;