Zeal on linux is ignoring the first parameter (the query)

it seems on linux the following will omit the first parameter when passed to zeal
```
xdg-open "dash-plugin:query=shared_ptr&keys=cpp,net,boost,qt,cvcpp,cocos2dx,c,manpages"
```
while the following works just fine
```
xdg-open "dash-plugin://query=shared_ptr&keys=cpp,net,boost,qt,cvcpp,cocos2dx,c,manpages"
```
According to https://kapeli.com/dash_plugins the dash-plugin format is dash-plugin://keys={keywords}&query={query} which matches my expectation for uri.

It seems in 137f5b30a96d89e58316fcbdbf8bce4a21726b9d you explicitly avoided this, but I'm not sure what the rational behind this was. Rolling back this change seems to fix the issue for me.

Zeal version 0.3.1
atom-dash 1.7.1