Bug in 3.3.0: accidental creation of global.signal, gets caught in strict UTs

[oliverlockwood]

Reproduction scenario:

• .mocharc.json containing "check-leaks": true,
• a mocha UT which makes a Needle request
• needle version 3.3.0
• the test starts failing with Error: global leak(s) detected: 'signal'

Investigation and debugging proved the issue was a rogue semicolon that should have been a colon.
Perhaps an argument in favour of separate var declarations instead of a block of them?
In any case, it's a 1-character fix, which I will raise as a PR very shortly.

This bug was not in Needle 3.2.0.