Add ostensibly unnecessary null check

apache2/re_variables.c

@@ -1431,6 +1431,7 @@ static int var_multipart_part_headers_generate(modsec_rec *msr, msre_var *var, m
 
         /* If we had a match add this argument to the collection. */
         if (match) {
+            if (parts[i]->header_lines) { /* this NULL check shouldn't be necessary */
                 for (j = 0; j < parts[i]->header_lines->nelts; j++) {
                     char *header_line = ((char **)parts[i]->header_lines->elts)[j];
                     msre_var *rvar = apr_pmemdup(mptmp, var, sizeof(msre_var));
@@ -1445,6 +1446,7 @@ static int var_multipart_part_headers_generate(modsec_rec *msr, msre_var *var, m
 	        }
             }
         }
+    }
 
     return count;
 }