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

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https://hg.mozilla.org/integration/gaia-central/rev/720110439216
Author: Fernando Rodriguez Sela <frsela@tid.es>
Desc: Merge branch 'STK_DSDS/Bug951586'

Bug 951586 - [DSDS][STK] Suport multiple cards in system STK code, r=timdream

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https://hg.mozilla.org/integration/gaia-central/rev/8a5adbbfe352
Author: Fernando Rodriguez Sela <frsela@tid.es>
Desc: Bug 951586 - [DSDS][STK] Suport multiple cards in system STK code, r=timdream
Bumping manifests a=b2g-bump