Add mailmap

Change-Id: I86936b1c5b513ee191052279f47a7a2793c0b582

.mailmap

diff --git a/.mailmap b/.mailmap
new file mode 100644
index 0000000..8154169
--- /dev/null
+++ b/.mailmap
@@ -0,0 +1 @@
+Shawn Pearce <sop@google.com> Shawn O. Pearce <sop@google.com>