cmake: fix FindTarantool.cmake module

Patch adds a commit 'Fix FindTarantool.cmake script'
(c6bd906) that was implemented in http
v2 and later reverted in scope of issue with discard v2.

Follows up #90
Part of #134

cmake/FindTarantool.cmake

@@ -9,7 +9,8 @@ macro(extract_definition name output input)
 endmacro()
 
 find_path(TARANTOOL_INCLUDE_DIR tarantool/module.h
-  HINTS ENV TARANTOOL_DIR
+  HINTS ${TARANTOOL_DIR} ENV TARANTOOL_DIR
+  PATH_SUFFIXES include
 )
 
 if(TARANTOOL_INCLUDE_DIR)
@@ -26,22 +27,14 @@ include(FindPackageHandleStandardArgs)
 find_package_handle_standard_args(TARANTOOL
     REQUIRED_VARS TARANTOOL_INCLUDE_DIR VERSION_VAR TARANTOOL_VERSION)
 if(TARANTOOL_FOUND)
-    set(TARANTOOL_INSTALL_LIBDIR "${CMAKE_INSTALL_LIBDIR}/tarantool")
-    set(TARANTOOL_INSTALL_LUADIR "${CMAKE_INSTALL_DATADIR}/tarantool")
     set(TARANTOOL_INCLUDE_DIRS "${TARANTOOL_INCLUDE_DIR}"
-                               "${TARANTOOL_INCLUDE_DIR}/tarantool/")
+                               "${TARANTOOL_INCLUDE_DIR}/tarantool/"
+        CACHE PATH "Include directories for Tarantool")
+    set(TARANTOOL_INSTALL_LIBDIR "${CMAKE_INSTALL_LIBDIR}/tarantool"
+        CACHE PATH "Directory for storing Lua modules written in Lua")
+    set(TARANTOOL_INSTALL_LUADIR "${CMAKE_INSTALL_DATADIR}/tarantool"
+        CACHE PATH "Directory for storing Lua modules written in C")
 
-    if (NOT "${CMAKE_INSTALL_PREFIX}" STREQUAL "/usr/local" AND
-            NOT "${CMAKE_INSTALL_PREFIX}" STREQUAL "${_install_prefix}")
-        message(WARNING "Provided CMAKE_INSTALL_PREFIX is different from "
-            "CMAKE_INSTALL_PREFIX of Tarantool. You might need to set "
-            "corrent package.path/package.cpath to load this module or "
-            "change your build prefix:"
-            "\n"
-            "cmake . -DCMAKE_INSTALL_PREFIX=${_install_prefix}"
-            "\n"
-        )
-    endif ()
     if (NOT TARANTOOL_FIND_QUIETLY AND NOT FIND_TARANTOOL_DETAILS)
         set(FIND_TARANTOOL_DETAILS ON CACHE INTERNAL "Details about TARANTOOL")
         message(STATUS "Tarantool LUADIR is ${TARANTOOL_INSTALL_LUADIR}")