Update EVP_Cipher documentation some more.

It doesn't retain partial blocks but it DOES update internal cipher state. ssl/
depends on this property.

Change-Id: I1e44b612c2e1549e096de8b71726007dcbc68de3
Reviewed-on: https://boringssl-review.googlesource.com/2640
Reviewed-by: Adam Langley <agl@google.com>
1 file changed