lib-sieve: program client: Fixed bug in handling of result code from …

…remote program (script service).

It was sometimes passed through as data, meaning that the result code was missed.
This transiently resulted in programs seemingly returning invalid result codes, causing an error.

src/lib-sieve/util/program-client-remote.c

@@ -86,8 +86,6 @@ static ssize_t program_client_istream_read(struct istream_private *stream)
 			}
 		}
 
-		if ( ret == 0 || (ret < 0 && !stream->parent->eof) ) break;
-
 		if ( stream->buffer != NULL && pos >= 1 ) {
 			/* retain/hide potential return code at end of buffer */
 			reserved = ( stream->buffer[pos-1] == '\n' && pos > 1 ? 2 : 1 );
@@ -99,6 +97,8 @@ static ssize_t program_client_istream_read(struct istream_private *stream)
 			}
 		}
 
+		if ( ret == 0 || (ret < 0 && !stream->parent->eof) ) break;
+
 		if ( ret <= 0 && stream->parent->eof ) {
 			/* Parent EOF and not more data to return; EOF here as well */
 			stream->istream.eof = TRUE;