[gimp-help-2] quickreference: fix make dist in VPATH builds.

[Jehan Pagès <jehanp src gnome org>]

commit c7a542692e4c17d8fbb68e3dc7092d106a4bd229
Author: Jehan <jehan girinstud io>
Date:   Mon Jun 12 02:03:30 2017 +0200

    quickreference: fix make dist in VPATH builds.
    
    Get po files from $(srcdir). This fixes this kind of errors:
    msginit: cannot create output file "po/ca.po": No such file or directory

 quickreference/Makefile.am |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/quickreference/Makefile.am b/quickreference/Makefile.am
index bec7680..3b50e9e 100644
--- a/quickreference/Makefile.am
+++ b/quickreference/Makefile.am
@@ -6,7 +6,7 @@ QUICKREFERENCE_LINGUAS = $(filter $(ALL_LINGUAS), $(QUICKREFERENCE_ALL_LINGUAS))
 
 POT_FILES = $(srcdir)/po/gimp-keys.pot
 
-PO_FILES = $(foreach lang,$(filter-out en,$(QUICKREFERENCE_ALL_LINGUAS)),po/$(lang).po)
+PO_FILES = $(foreach lang,$(filter-out en,$(QUICKREFERENCE_ALL_LINGUAS)),$(srcdir)/po/$(lang).po)
 
 XSL_FILES = \
        stylesheets/keys-svg.xsl        \