Cirrus: add vendor_check_task

* Make sure that all vendored dependencies are in sync with the code and
  the vendor.conf by running `make vendor` with a follow-up status check
  of the git tree.

* Vendor ginkgo and gomega to include the test dependencies.

Signed-off-by: Chris Evic <cevich@redhat.com>
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

vendor/github.com/hpcloud/tail/tail_posix.go

@@ -0,0 +1,11 @@
+// +build linux darwin freebsd netbsd openbsd
+
+package tail
+
+import (
+	"os"
+)
+
+func OpenFile(name string) (file *os.File, err error) {
+	return os.Open(name)
+}