util: Check for file being NULL in DirectoryCommit

src/util/system.cpp

@@ -1047,8 +1047,10 @@ void DirectoryCommit(const fs::path &dirname)
 {
 #ifndef WIN32
     FILE* file = fsbridge::fopen(dirname, "r");
+    if (file) {
         fsync(fileno(file));
         fclose(file);
+    }
 #endif
 }