Merge pull request #195 from coryb/testing

minor LinuxBlockDevice refactor
update release to 2.1.47-dev
Merge pull request #196 from coryb/testing

if --block-device is used dont use flocking
update release to 2.1.48-dev
Merge pull request #197 from coryb/testing

fixes for --volume-id
update release to 2.1.49-dev
Merge pull request #198 from coryb/testing

set max delay for exponential delay on snapshot monitoring
update release to 2.1.50-dev
skip finalizing if provisioning fails