Remove exist check from doLegacySignVerify

exist requires the keystore exist permission which callers of
sign/verify may not have. Instead log key not found if begin returns
::KEY_NOT_FOUND.

Bug: 21658885
Change-Id: I8c42f3a636a248e3fb1f0344bf32667fce57f667
1 file changed
tree: 6ae6275b635c610d808319192aa488ac97bf7782
  1. keystore/
  2. keystore-engine/
  3. softkeymaster/