Fix ABI on dragonfly

Define dragonfly as legitimate value for elf notes and also updates the ABI
version which is different than FreeBSD. FreeBSD only needs whole numbers for
the version (e.g. 8,9,10) while DragonFly needs evenly numbered point versions
(e.g. 3.4, 3.6, 3.8).

The development branches are oddly numbered (e.g. 3.3, 3.5) but packages created
by these branches should be valid for the upcoming release, so 3.3 will round to
3.4 for the ABI version.
Remove usage of deprecated libarchive function

Add macro for older libarchive support like in FreeBSD 9 and FreeBSD 8
archive_read_finish is deprecated

Reported by:	John Marino
Fix multirepo

Reported by:	kwm
Fixes:		442
file_exists needs 2 arguments not just one

Conflicts:
	libpkg/pkg_repo.c
Return an error in case a update did faile in multi repository mode
Fix trying to delete dirs, during force reinstall, that should be kept.

Related to bda157aa3 b4dd0da6 65acd4e57
Fix `pkg check -d` and `pkg query %d` not returning missing deps

This needs to be a LEFT JOIN instead of INNER JOIN since the
package entry may be missing. It's still a valid dependency
though and should show up under PKG_LOAD_DEPS

Broken by 7021b09df
Fix some indentation
pkg repo -F create the file database along with the regular package repository.
Spelling

Reported by:	matthew@
Wording

Reported by:	matthew@
Fix `pkg install -R` not installing missing dependencies

This is fixed by including missing dependencies into the jobs
after including the upwards dependencies into the list.

Fixes #430
Fix grammar of usage
Use consistent 'usage:' syntax
pkg-convert.8: Add missing pkg-shell(8) reference
Add missing pkg-convert(8) references
Update document dates
pkg.8: Document 'convert' subcommand
Add missing pkg-convert(8) reference