FindCurses: Drop search for deprecated HP-UX cur_colr library

Since commit b22e2de8 (HPUX support, 2001-11-05) the FindCurses
module searches for a 'cur_colr' library, but that is not needed
anymore.  AFAICT, the cur_colr package was introduced in HP-UX 10.00 and
marked as deprecated in 10.30 by X/OPEN curses (which replaced the even
older HP curses in 10.10).

In order to use cur_colr after 10.10 you should use the
/usr/include/curses_colr when compiling.  Since FindCurses doesn't even
search that path the headers cannot possibly match out of the box.  If
users want cur_colr they can set the cache entries by hand.

There is no 64-bit version of cur_colr in 11.11PA and it will be gone
completely in 11.31PA:

  http://h21007.www2.hp.com/portal/download/files/unprot/STK/HPUX_STK/impacts/i964.html

It is simplest to drop cur_colr support from FindCurses since it was
only partially implemented anyway.
Merge topic 'FindCurses-no-cur_colr' into next

d931ba60 FindCurses: Drop search for deprecated HP-UX cur_colr library