cleaner: recursively delete info dirs

[gromgit]

Arch-specific build tool formulae (Homebrew/homebrew-core#79874) install their info files in #{info}/<arch> to avoid conflicts with the main tool formulae.

However, the info cleaner only removes #{info}/dir, so each tool's bottle includes #{info}/<arch>/dir, which causes install-time conflicts.

This PR fixes that by deleting all dirs under #{info}.

Before (#{info}/dir):

==> Cleaning
[...]
==> Fixing /usr/local/Cellar/grep/3.6/bin/ggrep permissions from 755 to 555
rm /usr/local/Cellar/grep/3.6/share/info/dir
==> Finishing up

After (#{info}/dir) -- no change:

==> Cleaning
[...]
==> Fixing /usr/local/Cellar/grep/3.6/bin/ggrep permissions from 755 to 555
rm /usr/local/Cellar/grep/3.6/share/info/dir
==> Finishing up

Before (#{info}/<arch>/dir):

==> Cleaning
[...]
==> Fixing /usr/local/Cellar/i686-elf-binutils/2.36.1_1/lib/i686-elf/bfd-plugins/libdep.so permissions from 755 to 444
==> Finishing up

After (#{info}/<arch>/dir) -- now removed:

==> Cleaning
[...]
==> Fixing /usr/local/Cellar/i686-elf-binutils/2.36.1_1/lib/i686-elf/bfd-plugins/libdep.so permissions from 755 to 444
rm /usr/local/Cellar/i686-elf-binutils/2.36.1_1/share/info/i686-elf/dir
==> Finishing up

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[BrewTestBot]

Review period will end on 2021-06-28 at 05:42:57 UTC.

[MikeMcQuaid]

Makes sense, thanks again @gromgit!

[BrewTestBot]

Review period skipped due to critical label.