BUG/MINOR: log: free logformat expr on compile failure in cfg_parse_log_profile

When lf_expr_compile() fails in cfg_parse_log_profile, the code leaves
without freeing the previously strdup()'d strings in target_lf->str and
target_lf->conf.file. Let's add a call to lf_expr_deinit() there to
release it.

It was harmless anyway since the startup will abort when this happens,
but better clean it because with increasingly dynamic setups, one day
it could become a runtime leak.

No backport is needed.

src/log.c

@@ -6743,6 +6743,7 @@ int cfg_parse_log_profile(const char *file, int linenum, char **args, int kwm)
 			                     SMP_VAL_FE_LOG_END, &errmsg)) {
 				ha_alert("Parsing [%s:%d]: failed to parse logformat: %s.\n",
 				         file, linenum, errmsg);
+				lf_expr_deinit(target_lf);
 				err_code |= ERR_ALERT | ERR_FATAL;
 				goto out;
 			}