msimtf: Sign-compare warning fix

[Andrew Talbot]

Changelog:
    msimtf: Sign-compare warning fix.

diff --git a/dlls/msimtf/main.c b/dlls/msimtf/main.c
index da675aa..45edf53 100644
--- a/dlls/msimtf/main.c
+++ b/dlls/msimtf/main.c
@@ -168,7 +168,7 @@ static HRESULT register_server(BOOL doregister)
     STRTABLEA strtable;
     STRENTRYA pse[1];
     static CLSID const *clsids[34];
-    int i = 0;
+    unsigned int i = 0;
 
     static const WCHAR wszAdvpack[] = {'a','d','v','p','a','c','k','.','d','l','l',0};