can't run .desktop without icon entry

[Victor gonzalez]

Ifound this bug during testing bugfix for ·1617348since I got a different error:

Enviroment:

current build number: 209
device name: frieza
channel: ubuntu-touch/rc-proposed/bq-aquaris-pd.en
last update: 2016-10-13 12:26:08
version version: 209
version ubuntu: 20161013
version device: 20160809.0
version custom: 20160831--42-26-vivid

Steps to reproduce:

1º Create a desktop entry without the icon entry (something like that):
[Desktop Entry]
Name=Sync Monitor
Comment=Ask for online account authentication if the token expires
Exec=/usr/lib/arm-linux-gnueabihf/sync-monitor/sync-monitor-helper %u
Terminal=false
Type=Application
Version=1.0
X-Ubuntu-Gettext-Domain=sync-monitor

2º Launch it from terminal or through adb shell:
/usr/lib/arm-linux-gnueabihf/sync-monitor/sync-monitor-helper --desktop-file-hint=/usr/share/applications/sync-monitor-helper.desktop

Current result: Error given https://pastebin.canonical.com/167856/

Expected result: App should launch