Allow for Nova to use os-brick from git

This option to install os-brick from git was only added
into lib/cinder previously. When testing all-in-one nodes
this worked fine, but if you have multi-node setups with
compute nodes that don't install any c-* services we
only get packaged os-brick. With this change non-cinder
nodes can now test against unreleased os-bricks.

Change-Id: Ibb7423d243d57852dada0b6298463bbdfc6dc63c
diff --git a/lib/os_brick b/lib/os_brick
new file mode 100644
index 0000000..690e321
--- /dev/null
+++ b/lib/os_brick
@@ -0,0 +1,29 @@
+#!/bin/bash
+#
+# lib/os_brick
+# Install **os-brick** python module from source
+
+# Dependencies:
+#
+# - functions
+# - DEST, DATA_DIR must be defined
+
+# stack.sh
+# ---------
+# - install_os_brick
+
+# Save trace setting
+_XTRACE_CINDER=$(set +o | grep xtrace)
+set +o xtrace
+
+
+GITDIR["os-brick"]=$DEST/os-brick
+
+# Install os_brick from git only if requested, otherwise it will be pulled from
+# pip repositories by requirements of projects that need it.
+function install_os_brick {
+    if use_library_from_git "os-brick"; then
+        git_clone_by_name "os-brick"
+        setup_dev_lib "os-brick"
+    fi
+}