core: ltc: fix double free in dsa_import()

Upstream commit 1e260eeaae43 ("fir coverity finding: dsa_import double
free").

Fixes: #1962
Signed-off-by: Jerome Forissier <[email protected]>

core/lib/libtomcrypt/src/pk/dsa/dsa_import.c

@@ -130,10 +130,12 @@ int dsa_import(const unsigned char *in, unsigned long inlen, dsa_key *key)
         PKA_DSA, tmpbuf, &tmpbuf_len,
         LTC_ASN1_SEQUENCE, params, 3);
       if (err != CRYPT_OK) {
+         XFREE(tmpbuf);
          goto LBL_ERR;
       }
 
       if ((err=der_decode_integer(tmpbuf, tmpbuf_len, key->y)) != CRYPT_OK) {
+         XFREE(tmpbuf);
          goto LBL_ERR;
       }
 
@@ -152,7 +154,6 @@ int dsa_import(const unsigned char *in, unsigned long inlen, dsa_key *key)
 
   return CRYPT_OK;
 LBL_ERR:
-   XFREE(tmpbuf);
    mp_clear_multi(key->p, key->g, key->q, key->x, key->y, NULL);
    return err;
 }