patch 9.0.1313: some settings use the current codepage instead of 'encoding'

Problem:    Some settings use the current codepage instead of 'encoding'.
Solution:   Adjust how options are initialized. (Ken Takata, closes #11992)
diff --git a/src/optionstr.c b/src/optionstr.c
index 6c9fd3a..8acbbf7 100644
--- a/src/optionstr.c
+++ b/src/optionstr.c
@@ -1054,9 +1054,12 @@
 	}
 
 #if defined(MSWIN)
-	// $HOME may have characters in active code page.
+	// $HOME, $VIM and $VIMRUNTIME may have characters in active code page.
 	if (varp == &p_enc)
+	{
 	    init_homedir();
+	    init_vimdir();
+	}
 #endif
     }