Improve documentation and messages for the new CMP0017

This patch incorporates the comments from Brad:
-some improvements to the documentation of CMP0017
-make the test QUIETLY search for zlib

Source/cmIncludeCommand.h

@@ -77,8 +77,7 @@ public:
       "CMake module directory. There is one exception to this: if the file "
       "which calls include() is located itself in the CMake module directory, "
       "then first the CMake module directory is searched and "
-      "CMAKE_MODULE_PATH afterwards. This behaviour is controlled by policy "
-      "CMP0017."
+      "CMAKE_MODULE_PATH afterwards. See also policy CMP0017."
       "\n"
       "See the cmake_policy() command documentation for discussion of the "
       "NO_POLICY_SCOPE option."

Source/cmPolicies.cxx

@@ -449,19 +449,20 @@ cmPolicies::cmPolicies()
 
     this->DefinePolicy(
     CMP0017, "CMP0017",
-    "Prefer files from CMAKE_ROOT/ when including from CMAKE_ROOT.",
-    "Starting with CMake 2.8.3, if a cmake-module shipped with CMake (i.e. "
-    "located in CMAKE_ROOT/Modules/) calls include() or find_package(), "
-    "the files located in CMAKE_ROOT/Modules/ are prefered over the files "
-    "in CMAKE_MODULE_PATH.  This makes sure that the modules belonging to "
+    "Prefer files from the CMake module directory when including from there.",
+    "Starting with CMake 2.8.4, if a cmake-module shipped with CMake (i.e. "
+    "located in the CMake module directory) calls include() or "
+    "find_package(), the files located in the the CMake module directory are "
+    "prefered over the files in CMAKE_MODULE_PATH.  "
+    "This makes sure that the modules belonging to "
     "CMake always get those files included which they expect, and against "
     "which they were developed and tested.  "
     "In call other cases, the files found in "
     "CMAKE_MODULE_PATH still take precedence over the ones in "
-    "CMAKE_ROOT/Modules/.  "
+    "the CMake module directory.  "
     "The OLD behaviour is to always prefer files from CMAKE_MODULE_PATH over "
-    "files from CMAKE_ROOT/Modules/.",
-    2,8,3,0, cmPolicies::WARN);
+    "files from the CMake modules directory.",
+    2,8,4,0, cmPolicies::WARN);
 }
 
 cmPolicies::~cmPolicies()

Tests/FindPackageTest/CMakeLists.txt

@@ -8,7 +8,7 @@ LIST(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR})
 # because otherwise FindPackageHandleStandardArgs.cmake from the current
 # directory is included (via CMAKE_MODULE_PATH).
 CMAKE_POLICY(SET CMP0017 NEW)
-FIND_PACKAGE(ZLIB)
+FIND_PACKAGE(ZLIB QUIET)
 
 # Look for a package that has a find module and may be found.
 FIND_PACKAGE(OpenGL QUIET)