innd: Fix :bytes metadata for dot-stuffed headers

Initial dots in header field names were counted whereas they shouldn't
have.

see #286

doc/pod/news.pod

@@ -54,6 +54,12 @@ is not.  Thanks to Enrik Berkhan for the patch for B<nnrpd>.
 
 =item *
 
+INN now properly handles header field names starting with a leading dot:
+B<innd> correctly computes the C<:bytes> metadata item of articles with such
+header field names.
+
+=item *
+
 Fixed the computation of the Bytes header field by B<pullnews> (in header-only
 mode with the B<-B> flag).
 

innd/art.c

@@ -877,6 +877,9 @@ ARTparseheader(CHANNEL *cp)
                     ARTcheckheader(cp, i - data->CurHeader);
                     data->CurHeader = i;
                 }
+                /* Remember that the line begins with a dot. */
+                if (bp->data[i] == '.')
+                    data->DotStuffedLines++;
             }
             if (bp->data[i] == '\r' && bp->data[i + 1] == '\n') {
                 cp->Next = i + 2;