Simplify logic for checking if report folder can be removed
diff --git a/scripts/abi_check.py b/scripts/abi_check.py
index afc2afe..30f38a9 100755
--- a/scripts/abi_check.py
+++ b/scripts/abi_check.py
@@ -48,7 +48,8 @@
         self.setup_logger()
         self.report_dir = os.path.abspath(report_dir)
         self.keep_all_reports = keep_all_reports
-        self.should_keep_report_dir = os.path.isdir(self.report_dir)
+        self.can_remove_report_dir = not (os.path.isdir(self.report_dir) or
+                                          keep_all_reports)
         self.old_repo = old_repo
         self.old_rev = old_rev
         self.new_repo = new_repo
@@ -280,7 +281,7 @@
                 )
             os.remove(self.old_dumps[mbed_module])
             os.remove(self.new_dumps[mbed_module])
-        if not self.should_keep_report_dir and not self.keep_all_reports:
+        if self.can_remove_report_dir:
             os.rmdir(self.report_dir)
         self.log.info(compatibility_report)
         return compliance_return_code