screen: create /run/screens also at install time

After 56db43e, the directory is created at boot time.
This means if one installs screen it won't work until
after the first reboot.

This commit fixes that by creating the directory also
at install time. Note that we still need to create the
directory at boot time, since /run is cleared (tmpfs).

srcpkgs/screen/INSTALL

@@ -0,0 +1,5 @@
+case "${ACTION}" in
+post)
+	install -dm 1777 run/screens
+	;;
+esac

srcpkgs/screen/template

@@ -1,7 +1,7 @@
 # Template file for 'screen'
 pkgname=screen
 version=4.8.0
-revision=4
+revision=5
 build_style=gnu-configure
 configure_args="--with-sys-screenrc=/etc/screenrc --enable-pam
  --enable-colors256 --enable-rxvt_osc --enable-telnet