[1.7] Spider model no longer supports rotation

Verification builds:
1.7.0.2 Release 1117901

Summary:
The spider bones no longer support custom rotation 

Impact:
This affects the Tiny Footprints texture pack and a piece of our content going through cert. Going forward this makes using the spider model more limiting due to the hard coded rotations

Repro Steps:

1. Download the Tiny Footprints texture pack from the Store
2. Create a new world with the TinyFootprints equipped and has Cheats enabled 
3. Type /summon spider
4. Observe the spider model
5. Repeat in a 1.6 build and observe the spider model having custom rotation

Observed Results: 
The spider model no longer supports custom rotation 

 

Expected Results: 
The spider continues to support custom rotation like it had in previous versions

Screenshots/Videos attached: 
Yes

 

Regression Build:
1.6 builds. Confirmed in 980905