Rails placed with setblock do not connect across chunk borders.

Verification Build: 1.7.0.13 RC4, 1.8.1.2 RC1, 1.9.0.15 RC5, 1.10.0.3 RC2

Partner Rank: 3

Summary:
Rails placed via /setblock usually connect, however they do not connect across chunk borders.

Impact:

Rails cannot be made to automatically connect across chunk borders in an upcoming map which will look strange to players and not work as they would expect, leading to negative reviews and worse sales.

Repro Steps:

1. Create a new flatworld.
2. Run the command `/setblock 0 4 0 rail`
3. Run the command `/setblock -1 4 0 rail`

Observed Results: 

The two rails, while being side by side, do not connect.

Expected Results: 
The rails connect, just as they would if the player had placed the second rail.

Screenshots/Videos attached: No