idec_dec.c, DecodeRemaining: Set decoder state to ERROR to prevent VP8ExitCritical to be called again
Change-Id: Id5f893f45c348e1c529680d930e640f780a73d4c
this avoids duplicates between these trees and dsp/, e.g., enc/tree.c,
dec/tree.c, making pulling the whole library source tree into one target
possible
BUG=webp:279
Change-Id: I060a614833c7c24ddd37bf641702ae6a5eef1775