Abdelilah Essiari <aes@george.lbl.gov> reports that for very small

Abdelilah Essiari <aes@george.lbl.gov> reports that for very small
records, EVP_EncodeUpdate() may misbehave.  This happens when there's
a record boundary between the two ending b64 equal signs, which makes
EVP_EncodeUpdate think there has been more than one EOF, and therefore
add an extra NUL at the end of the output buffer.  This fix corrects
that problem.