Bug 1059674 - Use AsynchShutdown.blocker() for AddonManager provider shutdown. r=Unfocused, r=Yoric, r=Mossop, a=sledru

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branch : GECKO330_2014101104_RELBRANCH
Bug 1074135 - Callback after exceptions when calling async provider methods. r=Unfocused, r=Mossop, a=sledru

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branch : GECKO330_2014101104_RELBRANCH