Revert "CMake: add usage of ccache if it's available"

This reverts commit 2576dd4692f95221226cc9e2f119a12641f41b2b.

Unfortunately I didn't manage to fix older combination of CMake+Clang with ccache.
Newer version of Clang that I use can't compile older FuzzyLite from VCMI repository anyway.

CMakeLists.txt

@@ -3,13 +3,6 @@ cmake_minimum_required(VERSION 2.8.12)
 # TODO:
 # 1) Detection of Qt5 and compilation of launcher, unless explicitly disabled
 
-# Configure ccache if available
-find_program(CCACHE_FOUND ccache)
-if(CCACHE_FOUND)
-	set_property(GLOBAL PROPERTY RULE_LAUNCH_COMPILE ccache)
-	set_property(GLOBAL PROPERTY RULE_LAUNCH_LINK ccache)
-endif(CCACHE_FOUND)
-
 # where to look for cmake modules
 set(CMAKE_MODULE_PATH ${CMAKE_HOME_DIRECTORY}/cmake_modules)