TBR: mojo.shared: Remove .v23 from all .gitignore files.

MultiPart: 12/25

Change-Id: I60dc726599c8ccad54c95922fcb0f5e0aa148d85
diff --git a/.gitignore b/.gitignore
index c2296ef..4209dc0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1 @@
 /.jiri
-#TODO(nlacasse): Get rid of .v23 below once v23->jiri transition is complete.
-/.v23
\ No newline at end of file