SOLARIS: Look for ncurses in ncurses/ncurses.h

Solaris 11+ has ncurses.h in ncurses/ncurses.h. Look for it there.

Without this, on Solaris 11.1 we will detect libncurses automatically
(because it lives in /usr/lib), but not ncurses.h (since it is in
ncurses/ncurses.h, not ncurses.h). So, we will fall back to curses.h,
but will try to link to libncurses, which, as you might guess, fails
with various undefined symbols.

Reviewed-on: http://gerrit.openafs.org/8874
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
(cherry picked from commit 81dd4878e7a71b5acfd7a6e6f9be26cd6ab28972)

Change-Id: I139296ae267ec057fc5ee11634d19ba36c8f8d6c
Reviewed-on: http://gerrit.openafs.org/8890
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Paul Smeddle <paul.smeddle@gmail.com>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>