Install vlc_keys.h

vlc_vout_display.h is installed and depends on it

src/Makefile.am

@@ -58,6 +58,7 @@ pluginsinclude_HEADERS = \
 	../include/vlc_inhibit.h \
 	../include/vlc_input.h \
 	../include/vlc_input_item.h \
+	../include/vlc_keys.h \
 	../include/vlc_main.h \
 	../include/vlc_md5.h \
 	../include/vlc_messages.h \
@@ -106,7 +107,6 @@ noinst_HEADERS = \
 	../include/vlc_interface.h \
 	../include/vlc_intf_strings.h \
 	../include/vlc_iso_lang.h \
-	../include/vlc_keys.h \
 	../include/vlc_memory.h \
 	../include/vlc_osd.h \
 	../include/vlc_pgpkey.h \