Parse failures silence the bot

[smashwilson]

[Sun Nov 08 2015 20:14:48 GMT-0500 (EST)] ERROR SyntaxError: Expected "$", "$(", "|", [^$|)] or end of input but ")" found.
  at peg$buildException (/var/pushbot/src/pushbot/node_modules/hubot-pipe/src/shell-parser.js:248:14)
  at Object.peg$parse [as parse] (/var/pushbot/src/pushbot/node_modules/hubot-pipe/src/shell-parser.js:498:13)
  at /var/pushbot/src/pushbot/node_modules/hubot-pipe/src/index.js:14:30
  at /var/pushbot/src/pushbot/node_modules/hubot/src/middleware.coffee:33:24
  at /var/pushbot/src/pushbot/node_modules/hubot/node_modules/async/lib/async.js:269:13
  at iterate (/var/pushbot/src/pushbot/node_modules/hubot/node_modules/async/lib/async.js:146:13)
  at Object.async.eachSeries (/var/pushbot/src/pushbot/node_modules/hubot/node_modules/async/lib/async.js:162:9)
  at Object.async.reduce (/var/pushbot/src/pushbot/node_modules/hubot/node_modules/async/lib/async.js:268:15)
  at /var/pushbot/src/pushbot/node_modules/hubot/src/middleware.coffee:46:13
  at process._tickCallback (node.js:419:13)