Why did etc.c.odbc move to core.sys.windows?

[singingbush]

Also, the commit that marked `etc.c.odbc.*` as scheduled for 
removal also deleted a ton of code and changed behaviour at the 
same time. Typically a deprecation is supposed to be done a good 
few releases before making breaking changes.

It was this commit in phobos that caused problems:

https://github.com/dlang/phobos/commit/88fd21e7368e8e2158a6ac75d43587c77886d6dd