msi: Avoid a potential NULL pointer dereference (coccicheck).

[Michael Stefaniuc]

The last "goto done" is for si == NULL. When MSI_GetSummaryInformationW
returns NULL there is a crash.
---
 dlls/msi/msi.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/dlls/msi/msi.c b/dlls/msi/msi.c
index 3170e6d..9c08d1b 100644
--- a/dlls/msi/msi.c
+++ b/dlls/msi/msi.c
@@ -551,7 +551,8 @@ static UINT MSI_ApplicablePatchW( MSIPACKAGE *package, LPCWSTR patch )
 
 done:
     msiobj_release( &patch_db->hdr );
-    msiobj_release( &si->hdr );
+    if (si)
+        msiobj_release( &si->hdr );
     return r;
 }
 
-- 
1.7.1