Bumping gaia.json for 4 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/c248dd57985e
Author: vingtetun <21@vingtetun.org>
Desc: Merge pull request #17225 from vingtetun/bug984158

Bug 984158 - Mispositioned progress bar when opening a bookmark on the h...

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https://hg.mozilla.org/integration/gaia-central/rev/e4b25559775f
Author: Vivien Nicolas <21@vingtetun.org>
Desc: Bug 984158 - Mispositioned progress bar when opening a bookmark on the homescreen. r=etienne

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https://hg.mozilla.org/integration/gaia-central/rev/ed162a3f20b9
Author: vingtetun <21@vingtetun.org>
Desc: Merge pull request #17224 from vingtetun/bug983739

Bug 983739 - Strange character in apps/communications/contacts/js/contac...

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https://hg.mozilla.org/integration/gaia-central/rev/68e5626f9015
Author: Vivien Nicolas <21@vingtetun.org>
Desc: Bug 983739 - Strange character in apps/communications/contacts/js/contacts_matcher.js. r=arcturus
Bumping manifests a=b2g-bump