FindRSVG.cmake: Fix CMake warnings

CMake Warning (dev) at /usr/share/cmake/Modules/FindPackageHandleStandardArgs.cmake:493 (message):
  The package name passed to find_package_handle_standard_args() (PkgConfig)
  does not match the name of the calling package (RSVG).  This can lead to
  problems in calling code that expects find_package() result variables
  (e.g., `_FOUND`) to follow a certain pattern.
Call Stack (most recent call first):
  /usr/share/cmake/Modules/FindPkgConfig.cmake:562 (find_package_handle_standard_args)
  CMakeModules/FindRSVG.cmake:2 (INCLUDE)
  CMakeLists.txt:771 (FIND_PACKAGE)
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) at /usr/share/cmake/Modules/FindPackageHandleStandardArgs.cmake:493 (message):
  The package name passed to find_package_handle_standard_args() (PkgConfig)
  does not match the name of the calling package (RSVG).  This can lead to
  problems in calling code that expects find_package() result variables
  (e.g., `_FOUND`) to follow a certain pattern.
Call Stack (most recent call first):
  /usr/share/cmake/Modules/FindPkgConfig.cmake:562 (find_package_handle_standard_args)
  CMakeModules/FindRSVG.cmake:6 (INCLUDE)
  CMakeLists.txt:771 (FIND_PACKAGE)
This warning is for project developers.  Use -Wno-dev to suppress it.

Signed-off-by: Andreas Sturmlechner <asturm@gentoo.org>

Author: a17r

CMakeModules/FindRSVG.cmake

@@ -1,10 +1,7 @@
 #use pkg-config to find various modues
-INCLUDE(FindPkgConfig OPTIONAL)
-
-IF(PKG_CONFIG_FOUND)
-
-    INCLUDE(FindPkgConfig)
+find_package(PkgConfig QUIET)
 
+IF(PkgConfig_FOUND)
     #Version 2.35 introduces the rsvg_cleanup function which is used
     PKG_CHECK_MODULES(RSVG librsvg-2.0>=2.35)