Contacts: fix a small grammatical error in the German translation

Change-Id: Ie28fc15b7c341e7ba0395399c48635e99efa0b9c
diff --git a/res/values-de/strings.xml b/res/values-de/strings.xml
index e32ad20..20b7e0d 100644
--- a/res/values-de/strings.xml
+++ b/res/values-de/strings.xml
@@ -207,7 +207,7 @@
     <string name="searching_vcard_title" msgid="4970508055399376813">"vCard wird gesucht."</string>
     <string name="import_from_sim" msgid="3859272228033941659">"Von SIM-Karte importieren"</string>
     <string name="import_from_sdcard" msgid="8550360976693202816">"Von SD-Karte importieren"</string>
-    <string name="export_to_sdcard" msgid="2597105442616166277">"An SD-Karte exportieren"</string>
+    <string name="export_to_sdcard" msgid="2597105442616166277">"Auf SD-Karte exportieren"</string>
     <string name="share_visible_contacts" msgid="890150378880783797">"Sichtbare Kontakte weiterleiten"</string>
     <string name="import_one_vcard_string" msgid="9059163467020328433">"Eine VCard-Datei importieren"</string>
     <string name="import_multiple_vcard_string" msgid="3810226492811062392">"Mehrere VCard-Dateien importieren"</string>