lua5.3: `go test` fails

[Pierre Neidhardt]

lua version: 5.3.4

Your latest commit e26bd17 introduced a regression and the tests don't pass anymore:

 go test -v -tags llua
=== RUN   TestGoStruct
--- PASS: TestGoStruct (0.00s)
=== RUN   TestCheckStringSuccess
--- PASS: TestCheckStringSuccess (0.00s)
=== RUN   TestCheckStringFail
--- PASS: TestCheckStringFail (0.00s)
=== RUN   TestPCallHidden
ciao
--- PASS: TestPCallHidden (0.00s)
=== RUN   TestCall
--- FAIL: TestCall (0.00s)
	lua_test.go:151: Wrong return value (2) got: <>
=== RUN   TestLikeBasic
Hello World!
--- FAIL: TestLikeBasic (0.00s)
	lua_test.go:195: Call to print returned error
=== RUN   TestLikeQuickstart
--- PASS: TestLikeQuickstart (0.00s)
=== RUN   TestLikeUserdata
--- PASS: TestLikeUserdata (0.00s)
=== RUN   TestStackTrace
--- PASS: TestStackTrace (0.00s)
=== RUN   TestIssue8
--- PASS: TestIssue8 (0.00s)
=== RUN   TestConv
--- PASS: TestConv (0.00s)
FAIL
exit status 1
FAIL	github.com/aarzilli/golua/lua	0.006s