Fix issue with newer amqp gem

All tests passed however installing the logagent gem pulled in gem
dependencies at different versions to those specified in the bundle. The
amqp gem in particular has changed where some class methods live, this
broke logagent on a fresh install with the configuration we currently
use.

next_channel_id method moved classes.

To fix this iv'e:

- upgraded the amqp gem to the latest version,
- used pessimistic version locking for the amqp gem in the gemspec to
  prevent future occurrences
- Added a test that connects to rabbitmq using next_channel_id to ensure
  it works as intended
- Bumped the gem version to from 1.3.0 to 1.3.1
- Changes the gemspec test_files field to by dynamically generated out
  of version controlled files only.
Bump version
Lock down the deps

- Lock down this gems deps to avoid problems as other scripts using the
system ruby may install newer gems.

- Lock down JSON gem to the one intalled from yum (has native
  extensions)
Fix tests that fail using live JSON version

- The two fixed tests failed when using the live JSON version, newer
  version seem less forgiving and don't error on bad JSON. In each of
  the tests the end result was to try and turn a timestamp into JSON as
  .delete on a hash returns the deleted value, not the hash minus the
  key and value.
Use json 1.5.4 not 1.5.1

- 1.5.4 is availble everywhere already, use the newer version
Pin eventmachine to production version (native extensions)

- Pin eventmachine dependency to production version it has native
  extensions.
Don't be so specific with versions in gemspec

Allow log_agent to run with minro gem upgrades for all gems.
Remove rabbitmq connection test

- Added to find cause of issues, does not actually test logagent code.
Fix tests for loading events minus captured and timestamp fields

- calling delete on a string not the hash, because parentheses in the
  wrong the place. Tests now correctly test loading a payload minus the
  specific fields.
Remove useless comments
Merge branch 'fix_issue_with_gem_deps'

Conflicts:
	lib/log_agent/version.rb