Replace src/ios copy with DEPS mirror.

BUG=webrtc:6934
R=ehmaldonado@webrtc.org
TBR=henrika@webrtc.org

Review-Url: https://codereview.webrtc.org/2659493002 .
Cr-Commit-Position: refs/heads/master@{#16300}
diff --git a/.gitignore b/.gitignore
index e8c80d0..d16f4f0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -40,6 +40,7 @@
 /base
 /build
 /buildtools
+/ios
 /mojo
 /out
 /testing