fix i18n build problem

There was a typo in install/po/Makefile.in which caused (some) of
the .po files to be overwritten because the test to see if a po
file existed had a typo in it.

This patch also removes the unnecessary rebuilding of the pot which was
happening when using the "all" target (the default). The pot file now
must be manually remade, which is what we want.

Added a new target "mo-files" to manually generate the .mo files.
This is useful to run before checking in a new .po file just to
assure it "compiles" and we don't have to discover this during a
build.

install/po/Makefile.in

@@ -160,7 +160,7 @@ POTFILES = $(PYTHON_POTFILES) $(C_POTFILES)
 .SUFFIXES: .po .mo
 .PHONY: all create-po update-po update-pot install mostlyclean clean distclean test_lang test
 
-all: $(po_files)
+all:
 	@
 
 SUFFIXES = .po .mo
@@ -170,7 +170,7 @@ SUFFIXES = .po .mo
 	$(MSGFMT) -c -o t-$@ $< && mv t-$@ $@
 
 $(po_files): $(DOMAIN).pot
-	@if [ ! -f @a ]; then \
+	@if [ ! -f $@ ]; then \
 	    lang=`echo $@ | $(SED) -r -e 's/\.po$$//'` # Strip .po suffix ; \
 	    echo Creating nonexistent $@, you should add this file to your SCM repository; \
 	    $(MSGINIT) --locale $$lang --no-translator -i $(DOMAIN).pot -o $@; \
@@ -235,6 +235,9 @@ msg-stats:
                      printf "%-7s %8s %5.1f%% %4d po untranslated, %4d missing, %4d untranslated\n", \
                      po_name ":", ratio, translated/pot_count*100.0, po_untranslated, undefined, untranslated;}'; \
 	done
+
+mo-files: $(mo_files)
+
 install: $(mo_files)
 	@for lang in $(languages); do \
 	    dstdir=$(DESTDIR)$(localedir)/$$lang/LC_MESSAGES; \