gruel: change scoped_lock mutex to account for Boost deprecation

boost::mutex::scoped_lock is going away someday

boost::unique_lock<boost::mutex> is a drop-in replacement
blocks: fix use of bare boost::mutex::scoped_lock

gr_file_source
gr::blocks::file_source
Merge remote-tracking branch 'ncorgan/fedora-18-cmake' into maint
Merge remote-tracking branch 'ncorgan/cmake_boost_fix' into maint
Merge branch 'maint'
docs: fixed missed parameter documentation in fastnoise_source block.