setup_links.py: Remove third_party/libevent

It no longer exists in this location of Chromium and is thus
no longer needed.

NOTRY=True
TBR=tommi@webrtc.org

Review URL: https://codereview.webrtc.org/1893953002

Cr-Commit-Position: refs/heads/master@{#12398}
diff --git a/.gitignore b/.gitignore
index 5156e51..30e8d7f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -99,7 +99,6 @@
 /third_party/libc++
 /third_party/libc++-static
 /third_party/libc++abi
-/third_party/libevent
 /third_party/libFuzzer
 /third_party/libjingle
 /third_party/libjpeg
diff --git a/setup_links.py b/setup_links.py
index be59b26..90a0dd2 100755
--- a/setup_links.py
+++ b/setup_links.py
@@ -94,7 +94,6 @@
     'third_party/ijar',
     'third_party/jsr-305',
     'third_party/junit',
-    'third_party/libevent',
     'third_party/libxml',
     'third_party/mockito',
     'third_party/modp_b64',