[gnome-usage] Fix Catalan translation

[Jordi Mas <jmas src gnome org>]

commit 54a4f873ad8f4fcc864ba3440c7f74993275e7bd
Author: Jordi Mas <jmas softcatala org>
Date:   Sat Mar 3 15:36:32 2018 +0100

    Fix Catalan translation

 po/ca.po | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/po/ca.po b/po/ca.po
index 407c586..981d940 100644
--- a/po/ca.po
+++ b/po/ca.po
@@ -226,7 +226,7 @@ msgstr "Paperera"
 
 #: src/storage-item.vala:128
 msgid "Operating System"
-msgstr "Sistema Operatiu"
+msgstr "Sistema operatiu"
 
 #: src/storage-row.vala:248
 msgid "Empty"