Use a switch like try/finally for parallel break/continue/return/error

Cython/Compiler/Naming.py

@@ -97,14 +97,6 @@ binding_cfunc    = pyrex_prefix + "binding_PyCFunctionType"
 
 genexpr_id_ref = 'genexpr'
 
-# These labels are needed for break, return and exception paths through
-# parallel code sections. These are the variables that remember which path
-# should be taken after the parallel section
-parallel_error = pyrex_prefix + "parallel_error"
-parallel_return = pyrex_prefix + "parallel_return"
-parallel_break = pyrex_prefix + "parallel_break"
-parallel_continue = pyrex_prefix + "parallel_continue"
-
 line_c_macro = "__LINE__"
 
 file_c_macro = "__FILE__"