[4297] Corrected headers installation dir.

src/lib/cc/Makefile.am

@@ -15,7 +15,7 @@ libkea_cc_la_LDFLAGS = -no-undefined -version-info 1:0:0
 
 # Since data.h is now used in the hooks interface, it needs to be
 # installed on target system.
-libkea_cc_includedir = $(pkgincludedir)
+libkea_cc_includedir = $(pkgincludedir)/cc
 libkea_cc_include_HEADERS = data.h
 
 CLEANFILES = *.gcno *.gcda