Fix .gitignore to also include sub-directory bin/s

Ignores also these generated folders [1,2] after a local Eclipse build.

[1] ctf/bin/
[2] ftrace/bin/

Change-Id: I020598ce42e6438b36ff77fd058943e0cb292c44
Signed-off-by: Marco Miller <marco.miller@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/c/tracecompass/tracecompass-test-traces/+/197374
Tested-by: Trace Compass Bot <tracecompass-bot@eclipse.org>
Tested-by: Bernd Hufmann <bernd.hufmann@ericsson.com>
Reviewed-by: Bernd Hufmann <bernd.hufmann@ericsson.com>

.gitignore

@@ -2,6 +2,6 @@
 .classpath
 .project
 .settings/
-/bin/
+bin/
 MANIFEST.MF
 target/