Rename zuul-launcher to zuul-executor

To avoid confusion with nodepool-launcher, we've decided to rename
zuul-launcher to zuul-executor.

Change-Id: I7d03cf0f0093400f4ba2e4beb1c92694224a3e8c
Signed-off-by: Paul Belanger <pabelanger@redhat.com>
diff --git a/tests/fixtures/zuul-connections-multiple-gerrits.conf b/tests/fixtures/zuul-connections-multiple-gerrits.conf
index c1a335d..b3182d7 100644
--- a/tests/fixtures/zuul-connections-multiple-gerrits.conf
+++ b/tests/fixtures/zuul-connections-multiple-gerrits.conf
@@ -12,8 +12,8 @@
 git_user_name=zuul
 zuul_url=http://zuul.example.com/p
 
-[launcher]
-git_dir=/tmp/zuul-test/launcher-git
+[executor]
+git_dir=/tmp/zuul-test/executor-git
 
 [connection review_gerrit]
 driver=gerrit