CPT: Fix Problems with exceptions

Failure in an exec_subprocess call will trigger cleanup,
but cleanup calls exec_subprocess, resulting in recursion.

Possible uninitialized variable in exec_subprocess_check_output.

Signed-off-by: Vassil Vassilev <vvasilev@cern.ch>

tools/packaging/cpt.py

@@ -87,6 +87,7 @@ def exec_subprocess_call(cmd, cwd):
 
 def exec_subprocess_check_output(cmd, cwd):
     cmd = _convert_subprocess_cmd(cmd)
+    out = ''
     try:
         out = subprocess.check_output(cmd, cwd=cwd, shell=False,
                                       stdin=subprocess.PIPE, stderr=subprocess.STDOUT).decode('utf-8')
@@ -490,8 +491,14 @@ def tarball():
     tar.add(prefix, arcname=os.path.basename(prefix))
     tar.close()
 
-
+gInCleanup = False
 def cleanup():
+    global gInCleanup
+    if gInCleanup:
+        print('Failure in cleanup lead to recursion\n')
+        return 
+
+    gInCleanup = True
     print('\n')
     if args['skip_cleanup']:
         box_draw("Skipping cleanup")
@@ -540,6 +547,7 @@ def cleanup():
         if os.path.isdir(os.path.join(workdir, 'Install')):
             print('Remove directory: ' + os.path.join(workdir, 'Install'))
             shutil.rmtree(os.path.join(workdir, 'Install'))
+    gInCleanup = False
 
 
 ###############################################################################