Remove LIBPEERCONNECTION_LIB in GN to match GYP
Remove LIBPEERCONNECTION_LIB in GN to match GYP

BUG=None

Review URL: https://codereview.chromium.org/1407903010

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#358087}

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk