app-emulation/libguestfs: fix USE=fuse

Unfortunately, the configure check for --enable-fuse will silently
not build/install the fuse tools (rather than aborting) if fuse isn't found.

We were depending on fuse:= but libguestfs still specifically needs
fuse:0 (fuse2). Fedora's packaging does the same thing (checked because
the maintainer of the package in Fedora is involved upstream w/ libguestfs
too), even though I'm surpried to see stuff still needing fuse2.

This fixes installation of guestunmount etc.

Signed-off-by: Sam James <sam@gentoo.org>

app-emulation/libguestfs/libguestfs-1.48.6-r1.ebuild

@@ -70,7 +70,7 @@ COMMON_DEPEND="
 		dev-perl/String-ShellQuote
 	)
 	python? ( ${PYTHON_DEPS} )
-	fuse? ( sys-fs/fuse:= )
+	fuse? ( sys-fs/fuse:0 )
 	gtk? (
 		sys-apps/dbus
 		x11-libs/gtk+:3