l10n: de.po: translation fix for fall-back to 3way merge

The English version is correct, but misleading: It is not the 3way merge
that is being patched also, but that is being fallen back to also.

The German version translates the former meaning. Make it translate the
latter.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Ralf Thielow <ralf.thielow@gmail.com>

po/de.po

@@ -10491,7 +10491,7 @@ msgstr ""
 
 #: git-am.sh:166
 msgid "Falling back to patching base and 3-way merge..."
-msgstr "Falle zurück zum Patchen der Basis und des 3-Wege-Merges ..."
+msgstr "Falle zurück zum Patchen der Basis und zum 3-Wege-Merge ..."
 
 #: git-am.sh:182
 msgid "Failed to merge in the changes."