logReadCloser: ensure reader errors yield EOF

This change makes the underlying reader set their corresponding `eof` slot to true on termination.
This make the overall logReadCloser converge to EOF in case of errors of the underlying readers, therefore prevent spinning on read.

`bufio.Reader.ReadBytes` may not return io.EOF when `Close()` closes the underlying reader.
For instance, closing logReadCloser from the Scope App makes `bufio.Reader.ReadBytes` produce the following error: `http2: response body closed`.

probe/kubernetes/logreadcloser.go

@@ -130,7 +130,6 @@ func (l *logReadCloser) readInput(idx int) {
 			if len(line) > 0 {
 				l.dataChannel <- l.annotateLine(idx, line)
 			}
-			l.eofChannel <- idx
 			break
 		}
 		if err != nil {
@@ -139,6 +138,8 @@ func (l *logReadCloser) readInput(idx int) {
 		}
 		l.dataChannel <- l.annotateLine(idx, line)
 	}
+
+	l.eofChannel <- idx
 }
 
 func (l *logReadCloser) annotateLine(idx int, line []byte) []byte {