[conformal/btcchain] b4c55a: Update new time tests to prevent false positives.

[Dave Collins]

  Branch: refs/heads/master
  Home:   https://github.com/conformal/btcchain
  Commit: b4c55aee281e90baad00ee210f330d06ccb04093
      
https://github.com/conformal/btcchain/commit/b4c55aee281e90baad00ee210f330d06ccb04093
  Author: Dave Collins <da...@conformal.com>
  Date:   2014-10-11 (Sat, 11 Oct 2014)

  Changed paths:
    M mediantime_test.go

  Log Message:
  -----------
  Update new time tests to prevent false positives.

The new median time tests perform a comparsion of the adjusted time
returned from the median time source to the expected value.  However,
since time is always moving, it is possible the current time between the
call to the adjusted time function and the current time taken in the tests
for comparison just after the call differ by a second due to a boundary
condition.  So, this commit modifies the tests to allow for this
condition.