msi: Enumerate the current user's patches if szUserSid is NULL.

dlls/msi/registry.c

diff --git a/dlls/msi/registry.c b/dlls/msi/registry.c
index 57d30d7..ff0eee1 100644
--- a/dlls/msi/registry.c
+++ b/dlls/msi/registry.c
@@ -1883,8 +1883,15 @@
         MSIINSTALLCONTEXT *pdwTargetProductContext, LPWSTR szTargetUserSid,
         LPDWORD pcchTargetUserSid, LPWSTR *szTransforms)
 {
+    LPWSTR usersid = NULL;
     UINT r = ERROR_INVALID_PARAMETER;
 
+    if (!szUserSid)
+    {
+        get_user_sid(&usersid);
+        szUserSid = usersid;
+    }
+
     if (dwContext & MSIINSTALLCONTEXT_USERMANAGED)
     {
         r = msi_check_product_patches(szProductCode, szUserSid,
@@ -1922,6 +1929,7 @@
     }
 
 done:
+    LocalFree(usersid);
     return r;
 }