Remove incorrect usage of threading.Lock().

Not sure what the intention was - but the Lock is created locally in the function so nothing else would be waiting on that particular lock.

At some point we may wish to revisit other usages introduced in 1bb04279216e0abf4e24b9299cccc06c10b9c0ac.
Improvements to loading help text from tools.

Killing two birds with one stone. First is startup time -
PEP-8 fixes for lib/galaxy/tools/search/__init__.py.
Config option for disabling indexing of tool config.

This combined with the previous commit, shave over a second off (slightly more than 25%) Galaxy's startup time for the default toolbox on my laptop. Enable this option for functional tests - which will likely never care about seaching this index.
Fix bug with watch tool config option parsing.