gcom: Fix 'mode' option for ncm

gcom: Fix  'mode' option for ncm

For Huawei devices like E3372 proper command for set lte mode is:

AT^SYSCFGEX="03",3fffffff,2,4,7fffffffffffffff,,

Eval is required for proper quotation.

Without this fix:

Fri Nov  4 19:07:49 2016 daemon.notice netifd: Interface 'wan' is setting up now
Fri Nov  4 19:07:52 2016 daemon.notice netifd: wan (2060): sending -> AT
Fri Nov  4 19:07:52 2016 daemon.notice netifd: wan (2060): sending -> ATZ
Fri Nov  4 19:07:53 2016 daemon.notice netifd: wan (2060): sending -> ATQ0
Fri Nov  4 19:07:53 2016 daemon.notice netifd: wan (2060): sending -> ATV1
Fri Nov  4 19:07:54 2016 daemon.notice netifd: wan (2060): sending -> ATE1
Fri Nov  4 19:07:55 2016 daemon.notice netifd: wan (2060): sending -> ATS0=0
Fri Nov  4 19:07:55 2016 daemon.notice netifd: wan (2060): sending -> AT+CGDCONT=1,"IP","internet"
Fri Nov  4 19:07:57 2016 daemon.notice netifd: wan (2060): sending -> AT^SYSCFGEX=\"03\",3fffffff,2,4,7fffffffffffffff,,
Fri Nov  4 19:07:58 2016 daemon.notice netifd: wan (2060): Error running AT-command
Fri Nov  4 19:07:58 2016 daemon.notice netifd: wan (2060): Failed to set operating mode
Fri Nov  4 19:07:58 2016 daemon.notice netifd: wan (2092): Stopping network
...

With this fix:

Fri Nov  4 19:10:59 2016 daemon.notice netifd: Interface 'wan' is setting up now
Fri Nov  4 19:11:01 2016 daemon.notice netifd: wan (2539): sending -> AT
Fri Nov  4 19:11:01 2016 daemon.notice netifd: wan (2539): sending -> ATZ
Fri Nov  4 19:11:02 2016 daemon.notice netifd: wan (2539): sending -> ATQ0
Fri Nov  4 19:11:03 2016 daemon.notice netifd: wan (2539): sending -> ATV1
Fri Nov  4 19:11:03 2016 daemon.notice netifd: wan (2539): sending -> ATE1
Fri Nov  4 19:11:04 2016 daemon.notice netifd: wan (2539): sending -> ATS0=0
Fri Nov  4 19:11:05 2016 daemon.notice netifd: wan (2539): sending -> AT+CGDCONT=1,"IP","internet"
Fri Nov  4 19:11:06 2016 daemon.notice netifd: wan (2539): sending -> AT^SYSCFGEX="03",3fffffff,2,4,7fffffffffffffff,,
Fri Nov  4 19:11:07 2016 daemon.notice netifd: wan (2539): sending -> AT^NDISDUP=1,1,"internet"
Fri Nov  4 19:11:08 2016 daemon.notice netifd: wan (2539): Connected, starting DHCP on wwan0
Fri Nov  4 19:11:08 2016 daemon.notice netifd: Interface 'wan' is now up
Fri Nov  4 19:11:08 2016 daemon.notice netifd: Network device 'wwan0' link is up
Fri Nov  4 19:11:08 2016 daemon.notice netifd: Network alias 'wwan0' link is up
Fri Nov  4 19:11:08 2016 daemon.notice netifd: Interface 'wan_4' is enabled
Fri Nov  4 19:11:08 2016 daemon.notice netifd: Interface 'wan_4' has link connectivity
Fri Nov  4 19:11:08 2016 daemon.notice netifd: Interface 'wan_4' is setting up now
...

Signed-off-by: Cezary Jackiewicz <cezary@eko.one.pl>