TBR: lib: Remove .v23 from all .gitignore files.

MultiPart: 6/25

Change-Id: Ifbb07c592731edcf0c5f5082b59efc3de6d1ec0c
diff --git a/.gitignore b/.gitignore
index 5e2e933..4209dc0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1 @@
 /.jiri
-#TODO(nlacasse): Get rid of .v23 below once v23->jiri transition is complete.
-/.v23