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

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https://hg.mozilla.org/integration/gaia-1_4/rev/2b29b2687333
Author: Sergi Mansilla <sergi.mansilla@gmail.com>
Desc: Merge pull request #22303 from sergi/BUG_1024893_v1.4

Bug 1024893 - [dolphin][v1.4]Entering settings app takes more than 2.2s - uplifting to 1.4 [r=yurenju] [r=arthurcc]

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https://hg.mozilla.org/integration/gaia-1_4/rev/7cab26041dd8
Author: Sergi MAnsilla <sergi.mansilla@gmail.com>
Desc: Bug 1024893 - [dolphin][v1.4]Entering settings app takes more than 2.2s - 1.4 version

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https://hg.mozilla.org/integration/gaia-1_4/rev/74b0e159c9b6
Author: mpizza <mmm198219@gmail.com>
Desc: Bug 961563 - [TABLET] Support specifying target device type in Gaia build script.
Bumping manifests a=b2g-bump