bhyve: avoid resource leak

In bhyve_parse_config_option(), a string is allocated and passed to
nvlist_add_string() but not free'd afterwards.

Reported by:	Coverity
CID:		1544049
Sponsored by:	The FreeBSD Foundation

Reviewed by: imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/1234

usr.sbin/bhyve/bhyverun.c

@@ -593,6 +593,7 @@ bhyve_parse_config_option(const char *option)
 	if (path == NULL)
 		err(4, "Failed to allocate memory");
 	set_config_value(path, value + 1);
+	free(path);
 	return (true);
 }