Avoid "make distcheck" failure: newly-created man/*.1 files not removed

Avoid "make distcheck" failure: newly-created man/*.1 files not removed

* Makefile.am (EXTRA_DIST): Add .version.
(.version): New rule.
(dist-hook): Don't create $(distdir)/.version here, now that it's
being distributed.
* man/Makefile.am (common_dep): Use ../.version, not ../VERSION.
(../VERSION): Remove rule.
* GNUmakefile (dummy): Create .version, not VERSION.
Add an extra "...:= $(shell..." statement to ensure that
.version exists even when the preceding code is not run.
* .gitignore: Remove both .version and VERSION.

Signed-off-by: Jim Meyering <meyering@redhat.com>