Only install python-libguestfs bindings when needed

Currently those bindings are missing from SLES12, and since
they're not actually used unless file injection is enabled
(which is not by default), only conditionally depend on it.

Change-Id: I79a8d8ac7ad2fbd7d2fce696821d130218e43e03

lib/nova_plugins/functions-libvirt

@@ -28,7 +28,6 @@ function install_libvirt {
         else
             install_package qemu-kvm
             install_package libguestfs0
-            install_package python-guestfs
         fi
         install_package libvirt-bin libvirt-dev
         pip_install_gr libvirt-python
@@ -37,7 +36,6 @@ function install_libvirt {
         install_package kvm
         install_package libvirt libvirt-devel
         pip_install_gr libvirt-python
-        install_package python-libguestfs
     fi
 }
 

lib/nova_plugins/hypervisor-libvirt

@@ -26,7 +26,7 @@ source $TOP_DIR/lib/nova_plugins/functions-libvirt
 # --------
 
 # File injection is disabled by default in Nova.  This will turn it back on.
-ENABLE_FILE_INJECTION=${ENABLE_FILE_INJECTION:-False}
+ENABLE_FILE_INJECTION=$(trueorfalse False ENABLE_FILE_INJECTION)
 
 
 # Entry Points
@@ -60,7 +60,6 @@ function configure_nova_hypervisor {
         iniset $NOVA_CONF DEFAULT vnc_enabled "false"
     fi
 
-    ENABLE_FILE_INJECTION=$(trueorfalse False ENABLE_FILE_INJECTION)
     if [[ "$ENABLE_FILE_INJECTION" = "True" ]] ; then
         # When libguestfs is available for file injection, enable using
         # libguestfs to inspect the image and figure out the proper
@@ -97,6 +96,14 @@ function install_nova_hypervisor {
             yum_install libcgroup-tools
         fi
     fi
+
+    if [[ "$ENABLE_FILE_INJECTION" = "True" ]] ; then
+        if is_ubuntu; then
+            install_package python-guestfs
+        elif is_fedora || is_suse; then
+            install_package python-libguestfs
+        fi
+    fi
 }
 
 # start_nova_hypervisor - Start any required external services