fix gitignore for some git client
fix gitignore for some git client

Change-Id: I860094060683b4d4d8389e6662363ddfa2b13f89
Reviewed-on: https://dart-review.googlesource.com/c/86423
Reviewed-by: Martin Kustermann <a35dd5b79fac84b2bb3b026a16b8becc55af5961@google.com>

dart-archive/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk