Clear unused variables in X509_print_ex()

CLA: trivial

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18167)

crypto/x509/t_x509.c

diff --git a/crypto/x509/t_x509.c b/crypto/x509/t_x509.c
index 3e022cc..73f6489 100644
--- a/crypto/x509/t_x509.c
+++ b/crypto/x509/t_x509.c
@@ -55,7 +55,7 @@
 {
     long l;
     int ret = 0, i;
-    char *m = NULL, mlch = ' ';
+    char mlch = ' ';
     int nmindent = 0, printok = 0;
     EVP_PKEY *pkey = NULL;
     const char *neg;
@@ -222,7 +222,6 @@
     }
     ret = 1;
  err:
-    OPENSSL_free(m);
     return ret;
 }