Fix memory leak in crl2pkcs7 app

The crl2pkcs7 app leaks a stack of OPENSSL_STRINGs in error paths.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

apps/crl2p7.c

@@ -143,8 +143,6 @@ int crl2pkcs7_main(int argc, char **argv)
             }
         }
 
-    sk_OPENSSL_STRING_free(certflst);
-
     out = bio_open_default(outfile, 'w', outformat);
     if (out == NULL)
         goto end;
@@ -160,6 +158,7 @@ int crl2pkcs7_main(int argc, char **argv)
     }
     ret = 0;
  end:
+    sk_OPENSSL_STRING_free(certflst);
     BIO_free(in);
     BIO_free_all(out);
     PKCS7_free(p7);