fix crash when op->getDiversionAddress() return null

added 9 commits

• d8dfd346...61b0790d - 8 commits from branch master
• dabffc80 - fix crash when op->getDiversionAddress() return null

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mentioned in merge request linphone-sdk!172 (merged)

assigned to @smorlat

ok

added 2 commits

• ad5143df - 1 commit from branch master
• 7a5cd2bb - fix crash when op->getDiversionAddress() return null

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added 1 commit

• a891fb25 - fix crash when op->getDiversionAddress() return null

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merged