Install PostgresVersion.pm

A lamentable oversight on my part meant that when PostgresVersion.pm was
added in commit 4c4eaf3d provision to install it was not added to the
Makefile, so it was not installed along with the other perl modules.

src/test/perl/Makefile

@@ -23,11 +23,13 @@ install: all installdirs
 	$(INSTALL_DATA) $(srcdir)/SimpleTee.pm '$(DESTDIR)$(pgxsdir)/$(subdir)/SimpleTee.pm'
 	$(INSTALL_DATA) $(srcdir)/RecursiveCopy.pm '$(DESTDIR)$(pgxsdir)/$(subdir)/RecursiveCopy.pm'
 	$(INSTALL_DATA) $(srcdir)/PostgresNode.pm '$(DESTDIR)$(pgxsdir)/$(subdir)/PostgresNode.pm'
+	$(INSTALL_DATA) $(srcdir)/PostgresVersion.pm '$(DESTDIR)$(pgxsdir)/$(subdir)/PostgresVersion.pm'
 
 uninstall:
 	rm -f '$(DESTDIR)$(pgxsdir)/$(subdir)/TestLib.pm'
 	rm -f '$(DESTDIR)$(pgxsdir)/$(subdir)/SimpleTee.pm'
 	rm -f '$(DESTDIR)$(pgxsdir)/$(subdir)/RecursiveCopy.pm'
 	rm -f '$(DESTDIR)$(pgxsdir)/$(subdir)/PostgresNode.pm'
+	rm -f '$(DESTDIR)$(pgxsdir)/$(subdir)/PostgresVersion.pm'
 
 endif