[tex-live] `tlmgr info` is now broken when pointed at a nonexistent package

[jack]

Doing `tlmgr info foo`, where "foo" is a nonexistent package name, used to
result in this:

------------------
tlmgr: cannot find package foo, searching for other matches:

Packages containing `foo' in their title/description:

Packages containing files matching `foo':
------------------

But now it results in this: "Can't call method "get_package" on an
undefined value at /Users/gmn/.barn/texbin/tlmgr line 3719."

This is on macOS 10.12.6.

Also, I tried `tlmgr info beilstein` and got the above error, even though
my --repository is local and contains both:
  tlnet/archive/beilstein.source.tar.xz
  tlnet/archive/beilstein.tar.xz

-jack