imports: export VendorlessPath
imports: export VendorlessPath

Rename to avoid imports/import stutter and export.
It will be used soon by guru's referrers command.

This work supported by Sourcegraph.

Change-Id: Ibfc39d061d6269a336a59d9b6979188a94537d94
Reviewed-on: https://go-review.googlesource.com/108877
Run-TryBot: Josh Bleecher Snyder <cdc248cc4d32e4fbfe04e45228163bcecd48a0b9@gmail.com>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Alan Donovan <7069e9552f9d110b0a0f326b96f22f63fb99dfc1@google.com>

golang/tools,golang/tools,golang/tools,golang/tools,golang/tools