[babl] babl: remove lingering reference to rgb-constants.h in makefile

[Øyvind Kolås <ok src gnome org>]

commit fead2326f681a17b50ca40d6114592adcf18d698
Author: Øyvind Kolås <pippin gimp org>
Date:   Tue Aug 22 04:28:05 2017 +0200

    babl: remove lingering reference to rgb-constants.h in makefile

 babl/base/Makefile.am |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)
---
diff --git a/babl/base/Makefile.am b/babl/base/Makefile.am
index 5b92521..1b0fabe 100644
--- a/babl/base/Makefile.am
+++ b/babl/base/Makefile.am
@@ -23,7 +23,6 @@ libbase_la_SOURCES= $(h_sources) $(c_sources)
 libbase_la_LIBADD = $(MATH_LIB)
 
 EXTRA_DIST =           \
-       rgb-constants.h \
        util.h  \
        pow-24.h