modules: fix gtk-2.0 paths to gtk-3.0

Both print backends and configuration files for multipress are being
installed in the wrong directory, so let's fix that.

modules/input/Makefile.am

@@ -191,7 +191,7 @@ WAYLAND_MODULE = im-wayland.la
 endif
 endif
 
-multipress_defs = -DMULTIPRESS_LOCALEDIR=\""$(mplocaledir)"\" -DMULTIPRESS_CONFDIR=\""$(sysconfdir)/gtk-2.0"\"
+multipress_defs = -DMULTIPRESS_LOCALEDIR=\""$(mplocaledir)"\" -DMULTIPRESS_CONFDIR=\""$(sysconfdir)/gtk-3.0"\"
 im_multipress_la_CPPFLAGS = $(AM_CPPFLAGS) $(multipress_defs)
 libstatic_im_multipress_la_CPPFLAGS = $(im_multipress_la_CPPFLAGS)
 im_multipress_la_LDFLAGS = -rpath $(moduledir) -avoid-version -module $(no_undefined)

modules/printbackends/papi/Makefile.am

@@ -14,7 +14,7 @@ LDADDS = \
 	$(top_builddir)/gtk/libgtk-3.la	\
 	$(GTK_DEP_LIBS)
 
-backenddir = $(libdir)/gtk-2.0/$(GTK_BINARY_VERSION)/printbackends
+backenddir = $(libdir)/gtk-3.0/$(GTK_BINARY_VERSION)/printbackends
 
 backend_LTLIBRARIES = libprintbackend-papi.la