TT#8760 Add a ngcpcfg helper get_ngcp_version for the future usage

There are currently several places in templates where we do request
ngcp version, lets create a helper here, then we will be able to
switch on it after the next LTS is released (mr5.5).

Unfortunately we cannot switch on it before the next LTS,
otherwise upgrade mr4.4->mr5.5 may be corrupted by users.
If sp1 has been upgraded already and sp2 is not while
sp2 has received new templates already while ngcpcfg package
is still old -> templates cannot be built as helper is not found.

Change-Id: Icce966097335eddb7b09303ac2ef8081092bb8f3

lib/get_ngcp_version

@@ -0,0 +1,19 @@
+[%
+  # Returns the ngcp_version of the node calling this function.
+  #
+  # @return out		one of ['spce', 'sppro', 'carrier']
+-%]
+[% PERL -%]
+my $filename = '/etc/ngcp_upgrade_version';
+unless (-e $filename) {
+  $filename = '/etc/ngcp_version';
+}
+open my $hh, '<', $filename or die "Error opening $filename";
+my $ngcp_version = <$hh>;
+close $hh;
+chomp $ngcp_version;
+die "Fatal error retrieving ngcp_version [$ngcp_version]" unless length $ngcp_version;
+
+$stash->set(out => $ngcp_version);
+return;
+[% END -%]