My Dratini didn't evolve into what it was supposed to be, it just evolved into a normal one, and I was really excited about it. :\
Unfortunately, yours was probably a regular Dratini and I'm not sure what extreme levels of save corruption could remove shininess unintentionally. I'm actually a personal victim of this, too. I didn't know about the shiny sparkles and thought the Dratini I found in Fire Red was shiny, but nope, I was wrong.
The one on the left is normal, and on the right is shiny. From top to bottom, you have Fire Red/Leaf Green, Heart Gold/Soul Silver, and Silver. I'm not really sure why Dratini is purple in the Generation 3 sprites, especially compared to Dragonair:
Are you sure yours was shiny? Shiny Pokemon sparkle after being sent out in battle in almost every single game.