msi/tests: Write-strings warnings fix

[Andrew Talbot]

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

diff -urN a/dlls/msi/tests/db.c b/dlls/msi/tests/db.c
--- a/dlls/msi/tests/db.c	2006-07-28 17:23:46.000000000 +0100
+++ b/dlls/msi/tests/db.c	2006-07-28 18:29:10.000000000 +0100
@@ -1076,7 +1076,7 @@
 static void test_msiimport(void)
 {
     MSIHANDLE hdb, view, rec;
-    LPSTR query;
+    LPCSTR query;
     UINT r, count;
     signed int i;