translatable strings contain unnecessary formatting

[Benno Schulenberg]

In libparted/labels/fdasd.c and libparted/labels/vtoc.c the 
functions that print out error messages put several "%s" and "\n" 
in the gettextized strings, unnecessarily  Patches that make this 
simpler are coming up in a minute.

The patches also gettextize a few messages that were overlooked.

Further, vtoc.c speaks of "opening device '%s'", for example, but 
what is filled in for '%s' is a function name, not a device name.  
The first patch corrects also this.

And as an aside: the vtoc.c file does not contain a license yet.

Benno