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/stack.sh b/stack.sh
index 6fbb0be..5a5a040 100755
--- a/stack.sh
+++ b/stack.sh
@@ -570,6 +570,7 @@
 source $TOP_DIR/lib/ldap
 source $TOP_DIR/lib/dstat
 source $TOP_DIR/lib/dlm
+source $TOP_DIR/lib/os_brick
 
 # Extras Source
 # --------------
@@ -796,6 +797,11 @@
     install_heatclient
 fi
 
+# Install shared libraries
+if is_service_enabled cinder nova; then
+    install_os_brick
+fi
+
 # Install middleware
 install_keystonemiddleware