[automerger] Adjust URI host parsing to stop on \ character. am: fa3afbd0e7 am: 97668ae137 am: fddbf1b6b2 am: d3c0db66b9 am: 373cfa75c0 am: bdff04aba3 am: 7341805cac am: 885a2ecf96

Change-Id: Ie23e4a58c906b1afe4e47e915251d44c628c9a72