Bumping gaia.json for 3 gaia revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-2_1/rev/5ebabc477e05
Author: Dave Hunt <dave.hunt@gmail.com>
Desc: Bug 1049723 - Post logs to Treeherder report. r=rwood r=jlal a=test-only

========

https://hg.mozilla.org/integration/gaia-2_1/rev/2470eac75dfb
Author: Dave Hunt <dave.hunt@gmail.com>
Desc: Bug 1049723 - Exclude the artifact path from the link in Treeherder. r=rwood a=test-only

========

https://hg.mozilla.org/integration/gaia-2_1/rev/12c375f96e98
Author: Dave Hunt <dave.hunt@gmail.com>
Desc: Bug 1049723 - Replaced Treeherder command line options with environment variables. r=rwood a=test-only
Bumping manifests a=b2g-bump