Adding installation Heat package after cloning

There are two important reasons for this change:
 - Other OpenStack components contain this code already.
 - Heat store references on client/constraint/version plugins in
   setup.cfg and and stevedore uses these references, so we should
   install Heat after changing this part of code. As example look patch
   https://review.openstack.org/#/c/86978/ for grenade job, where
   heat-engine can not find two constrainsts due to changing their code
   place between releases.

Change-Id: Ic6b1f70ec2d2c06002eb6877a747b7b84213c710
Closes-Bug: #1402985
diff --git a/lib/heat b/lib/heat
index 49ed533..4e72cae 100644
--- a/lib/heat
+++ b/lib/heat
@@ -73,7 +73,6 @@
 
 # configure_heat() - Set config files, create data dirs, etc
 function configure_heat {
-    setup_develop $HEAT_DIR
     if [[ "$HEAT_STANDALONE" = "True" ]]; then
         setup_develop $HEAT_DIR/contrib/heat_keystoneclient_v2
     fi
@@ -195,6 +194,7 @@
 # install_heat() - Collect source and prepare
 function install_heat {
     git_clone $HEAT_REPO $HEAT_DIR $HEAT_BRANCH
+    setup_develop $HEAT_DIR
 }
 
 # install_heat_other() - Collect source and prepare