Improve error checking in i2d_ASN1_bio_stream()

Improve error checking in i2d_ASN1_bio_stream()

The streaming BIO API is full of missing error checks. This diff reverts
the logic so that the single call to ASN1_item_i2d_bio() is error checked
(it has the usual 1/0 return values), unindents the bulk of the code and
propagates the SMIME_crlf_copy() return value (alos 1/0) to be the actual
error.

ok jsing