generate messages.po at upload time

.travis.yml

@@ -158,9 +158,12 @@ script:
 
       wget https://downloads.crowdin.com/cli/v2/crowdin-cli.zip
       unzip -j crowdin-cli.zip
-      java -jar crowdin-cli.jar upload -b master
-      java -jar crowdin-cli.jar pull -b master
 
+      make messages.po
+      java -jar crowdin-cli.jar upload -b master
+      make clean
+
+      java -jar crowdin-cli.jar pull -b master
       # Try to only commit if translations changed.  Crowdin will update all
       # files when a new translation string is added but we don't need to
       # commit those until folks actually translate the new strings.