Ticket #4070: misc/Makefile.am: install mc.lib only once.

Before the change mc.lib was installed twice due to being
in two _DATA variables:

dist_pkgdata_DATA = \
        mc.lib

pkgdata_DATA = \
        $(dist_pkgdata_DATA) \
        $(PKGDATA_OUT)

This causes occasional install failures when two parallel
`/usr/bin/install` calls race in installing the file:

$ make -j20 DESTDIR=/var/tmp/portage/app-misc/mc-4.8.24/image install
...
 /usr/lib/portage/python3.6/ebuild-helpers/xattr/install \
    -c -m 644 mc.lib '/var/tmp/portage/app-misc/mc-4.8.24/image/usr/share/mc'
 /usr/lib/portage/python3.6/ebuild-helpers/xattr/install \
    -c -m 644 mc.lib mc.charsets '/var/tmp/portage/app-misc/mc-4.8.24/image/usr/share/mc'
...
 /usr/bin/install: cannot create regular file
   '/var/tmp/portage/app-misc/mc-4.8.24/image/usr/share/mc/mc.lib': File exists

After the change mc.lib is present only in dist_pkgdata_DATA.

Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Signed-off-by: Andrew Borodin <aborodin@vmail.ru>

misc/Makefile.am

@@ -17,7 +17,6 @@ dist_pkgdata_DATA = \
 	mc.lib
 
 pkgdata_DATA = \
-	$(dist_pkgdata_DATA) \
 	$(PKGDATA_OUT)
 
 SCRIPTS_IN = \
@@ -54,7 +53,6 @@ EXTRA_DIST = \
 	$(LIBFILES_SCRIPT) \
 	$(SCRIPTS_IN) \
 	$(noinst_DATA) \
-	$(dist_pkgdata_DATA) \
 	$(PKGDATA_IN)
 
 install-data-hook: