deps: edit v8 gitignore to allow trace_event copy

PR-URL: #4722
Reviewed-By: Ben Noordhuis <[email protected]>
Reviewed-By: Michaël Zasso <[email protected]>

Author: ofrobots

deps/v8/.gitignore

@@ -40,7 +40,6 @@ gcsuspects
 shell
 shell_g
 /_*
-/base/trace_event/common
 /build/Debug
 /build/gyp
 /build/ipch/