Install vlc_keys.h

vlc_vout_display.h is installed and depends on it
(cherry picked from commit 3649531c52025d4b564d53ee6914305670cf11c1)
Signed-off-by: Rafaël Carré <funman@videolan.org>

src/Makefile.am

@@ -59,6 +59,7 @@ 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 \
@@ -107,7 +108,6 @@ 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 \