[389-devel] Please review: [389 Project] #536: Clean up compiler warnings for 1.3

[Noriko Hosoi]

https://fedorahosted.org/389/ticket/536

https://fedorahosted.org/389/attachment/ticket/536/0001-Trac-Ticket-536-Clean-up-compiler-warnings-for-1.3.patch

Description: Cleaning up compiler warnings by:
  - declaring config_get_schemamod in proto-slap.h
  - putting parentheses around assignment
  - explicitly casting to discard 'const'