Return and Break were broken

BreakException and ReturnException were wrapped in MuranoPlException
similar to other python exceptions. So they were never catch by the code
that expects them and thus those macros didn't work

Change-Id: I1a4e766a1f8a9926768acec24f09b5e7b0eb169a

murano/dsl/macros.py

@@ -37,7 +37,9 @@ class CodeBlock(expressions.DslExpression):
                 def action():
                     try:
                         expr.execute(context, murano_class)
-                    except dsl_exception.MuranoPlException:
+                    except (dsl_exception.MuranoPlException,
+                            exceptions.BreakException,
+                            exceptions.ReturnException):
                         raise
                     except Exception as ex:
                         raise dsl_exception.MuranoPlException.\