fix libext2fs info page name

fix libext2fs info page name

In Red Hat bug #481620 Jerry reported that the libext2fs info page
is not accesable via "info libext2fs" but is via "info libext2fs.info"
and suggested that the following change should fix it.

Additional info from Jerry:
The problem is that makeinfo 4.12 interprets the dot in "libext2fs.info"
to be the end of the description portion of the info entry, even though
it hasn't seen the closing parenthesis yet.  Making the reference be to
just "libext2fs" works.

Addresses-Red-Hat-Bugzilla: #481620

Reported-by: Jerry James <loganjerry@gmail.com>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>