batctl: Merge bugfixes from v2017.4
* Handle allocation error in vlan_get_link_parse
* Simplify concatenation of pathnames
* tcpdump: Fix types for for TT v1
* Free nl_sock when if_nametoindex failed
* Free nl_sock on genl_ctrl_resolve error
* Handle nl_cb_alloc errors
* Handle nl_socket_alloc errors
* Handle nlmsg_alloc errors
* Handle allocation error for path_buff
* Handle failure during hash_iterator allocation
* Print dummy value when localtime failed
* suppress implicit-fallthrough compiler warning
* change PATH_BUFF_LEN to maximal possible value
Signed-off-by: Sven Eckelmann <[email protected]>