If a module has a suite.properties file in it the it cannot be added to another module suite but, more importantly, it
silently fails to alret the user when trying to add to another module suite.  In my case, the suite.properties came from
a previous module suite that the project had been removed from.

Reproducing the bug:

1) Create a module A and a module suite B.  Add module A to suite B (using "Add Existing").
2) Delete suite B folder from the disk (not using netbeans is the easiest way), leaving a suite.properties file in
module A that points nowhere.
3) Create a module suite C.  Add module A to module C (again, 'add existing').  Module C will not contain module A and
the IDE will not show the dependency.  Yet, there will be no dialog or alert.  The only way to know what happened is to
have the global logger open, which shows a stack trace that says that suite.properties already exists.

Expected behavior: 
There is already a bug requesting that the module suite contain the link to the module rather than the other way around
for good reasons.  Until that happens, the module should either find a way to belong to multiple suites and it should
add themselves to them when asked or it should, at the very least, alert the user that the "add existing" request failed
as well as to why the request failed.