Bug 1069115 - Make bluetooth webapi marionette tests wait for transaction success when changing settings; r=echou

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extra : rebase_source : c4fdc80f904987c848bca4b839d8b3f36fefd667
Bug 1069115 - Make mobileconnection webapi marionette tests wait for transaction success when changing settings; r=vyang

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extra : rebase_source : d8423024d586f6cf976f05bbfd17664d45ba7bd9