Log Message:
The sed expression in the VALID_VERSION make function only works with gsed,
so add it to USE_TOOLS.

With the VALID_VERSION function working properly the soname of liblensfun
will now be 'liblensfun.so.0' and liblensfun.so.0 and
liblensfun.so.${PKGVERSION} will also now get installed.

Because the install process installs _three_ copys of liblensfun, delete two
and make them symlinks.

Bump PKGREVISION