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

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https://hg.mozilla.org/integration/gaia-1_4/rev/ddfe28f308f8
Author: David Flanagan <dflanagan@mozilla.com>
Desc: Merge pull request #18240 from davidflanagan/bug989847-v1.4

Merge pull request #17207 from JerryShih/bug-974807-handle-lost-context-...

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https://hg.mozilla.org/integration/gaia-1_4/rev/fef7c065c265
Author: David Flanagan <dflanagan@mozilla.com>
Desc: Merge pull request #17207 from JerryShih/bug-974807-handle-lost-context-in-gallery-redo-when-lose-master

Bug 989847 - Handle webgl context lose/restore event for gallery editor mode r=djf(cherry picked from commit a55eb67d0659327a8e4b64099fc76a634823fecd)
Bumping manifests a=b2g-bump