[bind10-dev] "from iterator" constructor of InputBuffer was removed

[JINMEI Tatuya / 神明達哉]

This new constructor you added in #1540 caused build failure:
http://git.bind10.isc.org/~tester/builder/BIND10/20120511160149-Solaris10-sparc-Sunstudio/logs/build.out

Actually it didn't seem to be used anywhere in the source tree except
for its own test, so I simply removed it with the test.  If the plan
was to use it later, please bear in mind that it has been removed and
simply restoring the same definition will cause the same error (but,
personally, I doubt the syntax sugar worth the possible trouble - as
its own definition shows, the caller can easily convert the
iterators to the parameters for the original constructor).

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JINMEI, Tatuya