remove confusing warning (#966)

remove confusing warning

Author: nsoranzo

docs/writing_how_do_i.rst

@@ -243,7 +243,6 @@ tool can be found `here <https://github.com/jmchilton/picard/commit/4df897438408
 These tests can then be run with the Planemo `test command
 <http://planemo.readthedocs.org/en/latest/commands.html#test-command>`__.
 
-.. warning:: This idiom does not work with the Tool Shed test automated framework at this time and so these tests will largely only pass with Planemo_.
 
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 \.\.\. test exit codes?