sqlite.Session.Attach does not respect tableName argument

[AdamSLevy]

When calling sqlite.Session.Attach, all tables are attached regardless of whether the argument tableName is empty or not.

The bug is cause by inadvertently shadowing the ctable variable:

sqlite/session.go

Lines 89 to 97 in 66f853b

	func (s *Session) Attach(tableName string) error {
	var ctable *C.char
	if tableName != "" {
	ctable := C.CString(tableName)
	defer C.free(unsafe.Pointer(ctable))
	}
	res := C.sqlite3session_attach(s.ptr, ctable)
	return reserr("Session.Attach", tableName, "", res)
	}

Because the variable is used within the if branch, the compiler doesn't flag it as unused.

Line 92 should be changed to

ctable = C.CString(tableName)