Fix crash

Author: dmex

phlib/util.c

@@ -2592,18 +2592,16 @@ NTSTATUS PhCreateProcessWin32Ex(
             LocalFree(cmdlineArgList);
         }
 
-        if (!RtlDoesFileExists_U(fileName->Buffer))
+        if (fileName && !RtlDoesFileExists_U(fileName->Buffer))
         {
             WCHAR buffer[MAX_PATH];
 
             // The user typed a name without a path so attempt to locate the executable.
             if (PhSearchFilePath(fileName->Buffer, L".exe", buffer))
                 PhMoveReference(&fileName, PhCreateString(buffer));
             else
-                fileName = NULL;
+                PhClearReference(&fileName);
         }
-        else
-            fileName = NULL;
     }
 
     newFlags = 0;