gss/mech: fix make_sasl_name ctx leak

The EVP_MD_CTX created in make_sasl_name() must be destroyed
to prevent a memory allocation leak.

Change-Id: I0b7f5b1b0f4f252bfcdaec755d09ed75de505f75

lib/gssapi/mech/gss_mo.c

@@ -203,6 +203,7 @@ make_sasl_name(OM_uint32 *minor, const gss_OID mech, char sasl_name[16])
     EVP_DigestUpdate(ctx, hdr, 2);
     EVP_DigestUpdate(ctx, mech->elements, mech->length);
     EVP_DigestFinal_ex(ctx, hash, NULL);
+    EVP_MD_CTX_destroy(ctx);
 
     memcpy(p, "GS2-", 4);
     p += 4;