po: correct Qt4 Ctrl+{H,L} translations

(This should maybe not be marked for translation at all. Only Russian
defines it to something different than Ctrl+{H,L}.)

Adding whitespaces or translating "Ctrl" breaks Qt4 internals.

(cherry picked from commit feb479f2)

po/de.po

@@ -21225,7 +21225,7 @@ msgstr "Wiedergabeliste"
 
 #: modules/gui/qt4/menus.cpp:482
 msgid "Ctrl+L"
-msgstr "Strg+L"
+msgstr "Ctrl+L"
 
 #: modules/gui/qt4/menus.cpp:485
 msgid "Docked Playlist"
@@ -21237,7 +21237,7 @@ msgstr "Mi&nimale Ansicht"
 
 #: modules/gui/qt4/menus.cpp:497
 msgid "Ctrl+H"
-msgstr "Strg+H"
+msgstr "Ctrl+H"
 
 #: modules/gui/qt4/menus.cpp:506
 msgid "&Fullscreen Interface"