Bug 1022847 - toolkit/mozapps/update fails to compile with MinGW r=netzen

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extra : rebase_source : d876570cbfb29bc86cf1435f8e0f79eda49b5764
Bug 1022847 - Fixed --enable-metro build.

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extra : rebase_source : ac9e1609d5dd2211b819083a88dad6e26d2c6479