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

========

https://hg.mozilla.org/integration/gaia-central/rev/a5e18021bfd4
Author: Jose M. Cantera <jmcanterafonseca@gmail.com>
Desc: Merge pull request #22771 from jmcanterafonseca/fix_export_settings

Bug 1050843 - [B2G][Contacts] Export contacts buttons are overlaying Set...

========

https://hg.mozilla.org/integration/gaia-central/rev/9574473333c5
Author: Jose M. Cantera <jmcanterafonseca@gmail.com>
Desc: Bug 1050843 - [B2G][Contacts] Export contacts buttons are overlaying Settings menu page

========

https://hg.mozilla.org/integration/gaia-central/rev/ad7d5a90d0a1
Author: Jose M. Cantera <jmcanterafonseca@gmail.com>
Desc: Merge pull request #22778 from ADLR-es/fix-bug-1051538

Bug 1051538 - Linking contact never ends

========

https://hg.mozilla.org/integration/gaia-central/rev/df1d4e22e5a5
Author: Adrián de la Rosa <hola@adlr.es>
Desc: Bug 1051538 - Linking contact never ends
Bumping manifests a=b2g-bump