automake: Don't install libopenocd

Regular users (and probably no-one else either) have no use for this
library that is installed by default.

Change-Id: Ie94e1550cec33f26ef9b68e7ce4f46494f18e644
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/1479
Tested-by: jenkins
Reviewed-by: Xiaofan <xiaofanc@gmail.com>
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>