cabinet: Fix NULL pointer dereference (Coverity)

[Andrew Talbot]

Changelog:
    cabinet: Fix NULL pointer dereference (Coverity).

diff -urN a/dlls/cabinet/fci.c b/dlls/cabinet/fci.c
--- a/dlls/cabinet/fci.c	2006-09-12 23:59:28.000000000 +0100
+++ b/dlls/cabinet/fci.c	2006-09-26 18:27:03.000000000 +0100
@@ -176,18 +176,22 @@
   if ((!perf) || (!pfnalloc) || (!pfnfree) || (!pfnopen) || (!pfnread) ||
       (!pfnwrite) || (!pfnclose) || (!pfnseek) || (!pfndelete) ||
       (!pfnfcigtf) || (!pccab)) {
-    perf->erfOper = FCIERR_NONE;
-    perf->erfType = ERROR_BAD_ARGUMENTS;
-    perf->fError = TRUE;
+    if (perf) {
+      perf->erfOper = FCIERR_NONE;
+      perf->erfType = ERROR_BAD_ARGUMENTS;
+      perf->fError = TRUE;
+    }
 
     SetLastError(ERROR_BAD_ARGUMENTS);
     return NULL;
   }
 
   if (!((hfci = ((HFCI) (*pfnalloc)(sizeof(FCI_Int)))))) {
-    perf->erfOper = FCIERR_ALLOC_FAIL;
-    perf->erfType = ERROR_NOT_ENOUGH_MEMORY;
-    perf->fError = TRUE;
+    if (perf) {
+      perf->erfOper = FCIERR_ALLOC_FAIL;
+      perf->erfType = ERROR_NOT_ENOUGH_MEMORY;
+      perf->fError = TRUE;
+    }
 
     SetLastError(ERROR_NOT_ENOUGH_MEMORY);
     return NULL;