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

Change-Id: Ic81c538485759fbe10bd504409f0fde701d00c8d