remote_bitbang: Convert to use getaddrinfo()

Since gethostbyname() is deprecated and inconvenient, rewrite to use
getaddrinfo() using an implementation more or less copied from its man
page. This automatically enables support for IPv6.

This also fixes a FTBFS on ARM due to alignment issues.

Change-Id: I990a49506cac4b26faf77587937e506138371f7c
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/1379
Reviewed-by: Paul Fertser <fercerpav@gmail.com>
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>
remote_bitbang: De-duplicate init code and clean up on error

Change-Id: I8be413a9e1683f96f835232f9ff25d9bd42099de
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/1380
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>