remove jeweler, and fix to depend gem building on bundler

[tagomoris]

Fix Gemfile/Rakefile/gemspec to use bundler for building .gem
'jeweler' is not maintained today.

[repeatedly]

LGTM 👍

[tagomoris]

NOTE: someone must edit gem.description before first release with this gemspec

[frsyuki]

I agree jeweler is obsoleted and bundler is better.
But when we once switched to bundler, it caused a problem for RPM/deb packaging.
(b8871f8 and 165a572)
So we need to fix the packaging scripts first at the same time.

[frsyuki]

Sorry, this issue is taking time...

[tagomoris]

Ruby 2.0.0 doesn't have 'rubygems/builder', so we cannot rake build with jeweler...

[repeatedly]

treasure-data/td-agent@8e21c23

I tried above commit and building td-agent RPM succeeded on CentOS 6.4.

I am now trying deb package with bundler based fluentd.
But unfortunately, I can't build the deb package in the first place.
Need more time...

[suupic]

I switch jeweler to bundler and build rpm use td-agent's build script, it works fine

[repeatedly]

@suupic

build rpm use td-agnet's build script, it works fine

Which branch did you use, master or bundler-fluentd-support?

[suupic]

@repeatedly
I use master, but I replaced Rakefile and fluentd.gemspec. Those two file come from branch goodbye-jeweler.
but I only tied rpm, not deb