* guix/import/npm-binary.scm (<package-revision>)[license]: Handle the
case where a vector of licenses is used.
* tests/npm-binary.scm (foo-json): Redefine as a procedure with
license keyword.
(test-source-hash): Redefine with direct reference to test-source.
(foo-sexp): Redefine as a procedure with license keyword.
(npm-binary->guix-package test): Use foo-json and foo-sexp.
(npm-binary->guix-package with multiple licenses): Add test.
Change-Id: I9d6adb2ae2820678260fed1a67e91e22feb448b8
Signed-off-by: Jelle Licht <jlicht@fsfe.org>