perform install_infra sooner in stack.sh

The install_infra() call needs to be done earlier since
pip_install_gr() depends on it. Also the fact that python module names
are supposed to be lower case but some use camel case is a problem
(for example with XenAPI).

Change-Id: I7012d77134fa0d9c746d87e837934e7dcb337e5c
Closes-Bug: #1441820

inc/python

@@ -137,7 +137,7 @@ function pip_install {
 # get_from_global_requirements <package>
 function get_from_global_requirements {
     local package=$1
-    local required_pkg=$(grep -h ^${package} $REQUIREMENTS_DIR/global-requirements.txt | cut -d\# -f1)
+    local required_pkg=$(grep -i -h ^${package} $REQUIREMENTS_DIR/global-requirements.txt | cut -d\# -f1)
     if [[ $required_pkg == ""  ]]; then
         die $LINENO "Can't find package $package in requirements"
     fi

stack.sh

@@ -714,6 +714,9 @@ fi
 # Extras Pre-install
 # ------------------
 
+# Install required infra support libraries
+install_infra
+
 # Phase: pre-install
 run_phase stack pre-install
 
@@ -733,9 +736,6 @@ fi
 
 echo_summary "Installing OpenStack project source"
 
-# Install required infra support libraries
-install_infra
-
 # Install Oslo libraries
 install_oslo