create an 'if your eclipse update fails' FAQ entry or section in the "Update Software" guide

We've seen this now and again that upgrading from one version of Fuse IDE to another fails. We're still trying to figure out the exact causes to hopefully avoid this ever happening.

If it does happen & we find out about it, hopefully we can make a new release that works around the problem. However currently if you upgrade 1.1.2 -> 1.1.3 -> 1.1.4 in order, it can fail. (Though 1.1.0 -> 1.1.4 or 1.1.2 -> 1.1.4 is totally fine!).

When an update fails the work around is to uninstall Fuse IDE and then install it again. (Unfortuately we've not figured out how to make this automatic).

e.g. on OS X

Eclipse -> About Eclipse -> Installation Details button (bottom left) -> HIghlight Fuse IDE in tree -> click Uninstall button.

Then try an install again and you're good to go.

So maybe add a little section about if you don't seem to be able to open Fuse IDE on restart after an update here:
http://fusesource.com/docs/ide/camel/1.0/install_guide/install_guide.html#RiderUpgrade

then uninstall and re-install.

One minor nit we could mention; if you try open camelContext.xml after a "bad update" you'll get an XML editor opened. If you then uninstall & reinstall its fine, though the editor remembers you've opened it with "XML Editor" so you need to do right click -> Open With -> Fuse IDE to force it to open in Fuse IDE again