Fix off-centered hostname

[Samq64]

Resolves #85

Removes the duplicate spacer from the left side of the hostname in the default panel configuration so it centers properly.

I'm not a C developer and didn't test my changes, but this is just a hotfix, so it should probably be fine.

[bluesabre]

This doesn't quite fix it, just moves the problem to the left.

Since it's broken, we should probably move the default to left and right. Here's what Xubuntu does:

indicators=~host;~spacer;~session;~language;~a11y;~clock;~power;

[Samq64]

Since Xubuntu already defaults to it I pushed your suggestion. I actually compiled and tested this time.