Remove unnecessary execute permissions

These files have acquired execute permissions that
are not strictly necessary because they are being 
sourced, and not intended to be run separately.

Restore to 644

Change-Id: I0b8654123416a07521502b61610ca45c94494a07
diff --git a/lib/neutron-legacy b/lib/neutron-legacy
old mode 100755
new mode 100644
diff --git a/lib/neutron_plugins/linuxbridge_agent b/lib/neutron_plugins/linuxbridge_agent
old mode 100755
new mode 100644
diff --git a/lib/neutron_plugins/ml2 b/lib/neutron_plugins/ml2
old mode 100755
new mode 100644
diff --git a/lib/neutron_plugins/openvswitch_agent b/lib/neutron_plugins/openvswitch_agent
old mode 100755
new mode 100644
diff --git a/lib/neutron_plugins/ovs_base b/lib/neutron_plugins/ovs_base
old mode 100755
new mode 100644
diff --git a/lib/nova_plugins/functions-libvirt b/lib/nova_plugins/functions-libvirt
old mode 100755
new mode 100644