Protect network-manger to start wo interface

Hi
On script 01ifupdown, when running from /etc/network/* interfaces may disapear.
On some network cards (Realteck) when running ethtool interface disappear.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: network-manager 0.9.10.0-4ubuntu15.1
Uname: Linux 4.1.0-999-generic i686
ApportVersion: 2.17.2-0ubuntu1
Architecture: i386
CurrentDesktop: Unity
Date: Sun May 17 17:23:23 2015
IpRoute:
 default via 192.168.0.1 dev eth0 proto static metric 1024
 169.254.0.0/16 dev eth0 scope link metric 1000
 192.168.0.0/24 dev eth0 proto kernel scope link src 192.168.0.3
IwConfig:
 lo no wireless extensions.

 eth0 no wireless extensions.
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
 WimaxEnabled=true
RfKill:

SourcePackage: network-manager
UpgradeStatus: No upgrade log present (probably fresh install)
mtime.conffile..etc.NetworkManager.dispatcher.d.01ifupdown: 2015-05-17T17:14:33.661334
nmcli-con:
 NAME UUID TYPE TIMESTAMP TIMESTAMP-REAL AUTOCONNECT READONLY DBUS-PATH ACTIVE DEVICE STATE ACTIVE-PATH
 Wired connection 1 60b1ac1d-2cc1-4119-a9ab-a80b67b15665 802-3-ethernet 1431872554 Sun 17 May 2015 05:22:34 PM EEST yes no /org/freedesktop/NetworkManager/Settings/0 yes eth0 activated /org/freedesktop/NetworkManager/ActiveConnection/0
nmcli-dev:
 DEVICE TYPE STATE DBUS-PATH CONNECTION CON-UUID CON-PATH
 eth0 ethernet connected /org/freedesktop/NetworkManager/Devices/1 Wired connection 1 60b1ac1d-2cc1-4119-a9ab-a80b67b15665 /org/freedesktop/NetworkManager/ActiveConnection/0
 lo loopback unmanaged /org/freedesktop/NetworkManager/Devices/0 -- -- --
nmcli-nm: Error: command ['nmcli', '-f', 'all', 'nm'] failed with exit code 2: Error: Object 'nm' is unknown, try 'nmcli help'.