Windows XP is 0x0501

See http://msdn.microsoft.com/en-us/library/aa383745.aspx

And as we support only XP as minimum change this.

Change-Id: Iad51b0dd4bb960ed5a270b0b701ec3e0b28ab4e2

fpicker/source/win32/filepicker/platform_xp.h

@@ -28,8 +28,8 @@
 #undef _WIN32_IE
 #undef _WTL_NO_CSTRING
 
-#define WINVER          0x0500
-#define _WIN32_WINNT    0x0500
+#define WINVER          0x0501
+#define _WIN32_WINNT    0x0501
 #define _WIN32_IE       0x0600
 #define _WTL_NO_CSTRING