ole32/tests: Write-strings warnings fix

[Andrew Talbot]

Changelog:
    ole32/tests: Write-strings warnings fix.

diff -urN a/dlls/ole32/tests/clipboard.c b/dlls/ole32/tests/clipboard.c
--- a/dlls/ole32/tests/clipboard.c	2006-05-23 13:48:25.000000000 +0100
+++ b/dlls/ole32/tests/clipboard.c	2006-08-03 18:24:47.000000000 +0100
@@ -297,7 +297,7 @@
     DataObjectImpl_EnumDAdvise
 };
 
-static HRESULT DataObjectImpl_CreateText(LPSTR text, LPDATAOBJECT *lplpdataobj)
+static HRESULT DataObjectImpl_CreateText(LPCSTR text, LPDATAOBJECT *lplpdataobj)
 {
     DataObjectImpl *obj;