[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 am: f16fc49b6a am: 4c2fb949c1

Change-Id: I808b58344b8ad7e89dd757e9b36c553a41713c69