groff: correct the install path of man.local

groff: correct the install path of man.local

openvswitch build failed due to wrong install path of man.local which is
provided by groff.

Error log:
  /yocto/build/tmp/sysroots/x86_64-linux/usr/share/groff/1.22.2/tmac/an-old.tmac:690:
  warning: can't find macro file `man.local'

(From OE-Core rev: 5f2dd65e758ead8177a1cdda047bdb105b96e208)

Signed-off-by: Zhenhua Luo <zhenhua.luo@freescale.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>