382. Briefly: fixing pdfstudio's leftover crud

I didn't like pdfstudio (http://verahill.blogspot.com.au/2013/02/338-annotating-pdfs-in-linux-revisited.html), not least because it's stuck in a microsoft world of 'basic' and 'pro' versions i.e. artificial crippling. I promptly got rid of it, but it has been lingering on my system like a bad relationship:

dpkg: warning: parsing file '/var/lib/dpkg/available' near line 94935 package 'pdfstudio':
 missing description

The simplest, most radical fix is to do

sudo dpkg --clear-avail
sudo apt-get update