Bumping gaia.json for 2 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/dd8495a9a99f
Author: Cristian Rodriguez <crdlc@tid.es>
Desc: Merge pull request #15650 from crdlc/bug-950622

Bug 950622 - [Download Manager] The % of the download is not displayed i...

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https://hg.mozilla.org/integration/gaia-central/rev/9b9181d17873
Author: crdlc <crdlc@tid.es>
Desc: Bug 950622 - [Download Manager] The % of the download is not displayed in a notification for files with long names
Bumping manifests a=b2g-bump