[automerger] Filter Attachment file name of forward slashes for .eml attachments. am: 53b40fd185 am: eb8ae2ec17 am: be56f65931 am: 6f463bac17 am: 015cde5a2b am: 1827d56264 am: 31ea2c26ff am: 3cb03481aa

Change-Id: Id56422cdf34d13720ed4301a37e1655e108caf0e