Add 'revert' example to git-drover docs.

man/src/git-drover.demo.2.sh

Index: man/src/git-drover.demo.2.sh
diff --git a/man/src/git-drover.demo.2.sh b/man/src/git-drover.demo.2.sh
new file mode 100755
index 0000000000000000000000000000000000000000..dcd07e4511f156e2efba442fe5ccbb5579dd63c4
--- /dev/null
+++ b/man/src/git-drover.demo.2.sh
@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+. git-drover.demo.common.sh
+
+echo "# Make sure we have the most up-to-date branch sources."
+run git fetch
+echo
+echo "# Checkout the branch with the change we want to revert."
+run git checkout -b drover_9999 branch-heads/9999
+echo
+drover_c "This change is horribly broken."
+echo "# Here's the commit we want to revert."
+run git log -n 1
+echo
+echo "# Now do the revert."
+silent git revert --no-edit $(git show-ref -s pick_commit)
+pcommand git revert $(git show-ref -s pick_commit)
+echo
+echo "# That reverted the change and committed the revert."
+run git log -n 1
+echo
+echo "# As with old drover, reverts are generally OK to commit without LGTM."
+pcommand git cl upload -r some.committer@chromium.org --send-mail
+run git cl land --bypass-hooks