Add missing -e flag to echo invocation

Without this, the \e... escape sequence is printed literally.

Change-Id: I6bdac0cc61073d52a718384a3c1349a964ffc71f
diff --git a/cogsetup.sh b/cogsetup.sh
index ef1485d..5c64a06 100644
--- a/cogsetup.sh
+++ b/cogsetup.sh
@@ -57,7 +57,7 @@
   fi
   function repo {
     if [[ "${PWD}" == /google/cog/* ]]; then
-      echo "\e[01;31mERROR:\e[0mrepo command is disallowed within Cog workspaces."
+      echo -e "\e[01;31mERROR:\e[0mrepo command is disallowed within Cog workspaces."
       return 1
     fi
     ${ORIG_REPO_PATH} "$@"