Install CMake files to lib/cmake/Ceres

This is the right thing to do since the CMake files contain target
specific information - share is only for target-independent files.
Without this patch, the CMake files will collide on distributions
that allow to install for multiple targets in parallel (e. g. on
Exherbo).

Change-Id: Iac17af63b9f9b25d0ca400c77c2b2e0e8a51196f

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index bfeeaa3..4d25fdf 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -760,7 +760,7 @@
 if (WIN32)
   set(RELATIVE_CMAKECONFIG_INSTALL_DIR CMake)
 else ()
-  set(RELATIVE_CMAKECONFIG_INSTALL_DIR share/Ceres)
+  set(RELATIVE_CMAKECONFIG_INSTALL_DIR lib/cmake/Ceres)
 endif ()
 
 # This "exports" for installation all targets which have been put into the