[infra] Remove tools.git from the infra manifest

The repo no longer contains anything.

Change-Id: I917aecf653f3a0d135a6a7d274c092a926d35ee2
diff --git a/infra b/infra
index d14ea12..007b86f 100644
--- a/infra
+++ b/infra
@@ -28,10 +28,6 @@
              path="fuchsia/recipes"
              remote="https://fuchsia.googlesource.com/infra/recipes"
              gerrithost="https://fuchsia-review.googlesource.com"/>
-    <project name="tools"
-             path="tools"
-             remote="https://fuchsia.googlesource.com/tools"
-             gerrithost="https://fuchsia-review.googlesource.com"/>
     <!-- CHROMIUM -->
     <project name="chromium/recipes-py"
              path="chromium/recipes-py"