remove SkImageEncoder_none.cpp

msarett@ realized that if all of the encoders were disabled, then it
is equivalent to SkImageEncoder.cpp.

Change-Id: Ib3d5d7d061e1a60d7081689430107fb250903d5c
Reviewed-on: https://skia-review.googlesource.com/20440
Reviewed-by: Matt Sarett <msarett@google.com>
Reviewed-by: Cary Clark <caryclark@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
2 files changed