Help: Fix configure_file call to use COPYONLY, not COPY_ONLY

The configure_file signature has option 'COPYONLY' (no underscore).
Fix the example in 'cmake-packages.7.rst'.
KWSys: Fix configure_file call to use COPYONLY, not COPY_ONLY
Qt4: Fix configure_file call to use COPYONLY, not COPY_ONLY
configure_file: Warn about unknown arguments

Extend the RunCMake.configure_file test with a case covering possible
common typos of the COPYONLY option.

Reported-by: Iosif Neitzke <iosif.neitzke@gmail.com>
Merge topic 'fix-configure_file-COPYONLY' into next

1531df2b configure_file: Warn about unknown arguments
4abbb140 Qt4: Fix configure_file call to use COPYONLY, not COPY_ONLY
bd7ba8e2 KWSys: Fix configure_file call to use COPYONLY, not COPY_ONLY
e9282782 Help: Fix configure_file call to use COPYONLY, not COPY_ONLY