Add empty placeholder LINGUAS file for pg_combinebackup.

This will eventually be replaced once some translations exist
for pg_combinebackup's messages.  In the meantime, we need
something here to prevent "make" from complaining in
builds with --enable-nls.  Per advice added in 88dad06b4.

diff --git a/src/bin/pg_combinebackup/po/LINGUAS b/src/bin/pg_combinebackup/po/LINGUAS
new file mode 100644 (file)
index 0000000..e69de29