[Bug 1274854] kubectl exec: handshake did not verify certificate chain

[Red Hat Bugzilla]

https://bugzilla.redhat.com/show_bug.cgi?id=1274854
Bug 1274854 depends on bug 1276255, which changed state.

Bug 1276255 Summary: golang-1.5 breaks tls handshake certificate chain verification
https://bugzilla.redhat.com/show_bug.cgi?id=1276255

What    |Removed                     |Added
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             Status|NEW                         |CLOSED
         Resolution|---                         |NOTABUG