1. Refactor sp_show_create_function() and sp_show_create_procedure()
  into show_create_routine().
2. Code cleanup: eliminate proxy functions.


sql/sp.cc:
  Code cleanup: eliminate proxy functions.
sql/sp.h:
  Code cleanup: eliminate proxy functions.
sql/sp_head.cc:
  1. Refactor sp_show_create_function() and sp_show_create_procedure()
    into show_create_routine().
  2. Code cleanup: eliminate proxy functions.
sql/sp_head.h:
  1. Refactor sp_show_create_function() and sp_show_create_procedure()
    into show_create_routine().
  2. Code cleanup: eliminate proxy functions.
sql/sql_parse.cc:
  Code cleanup: use new functions.