Add includes to UI files to resolve FTBFS

Signed-off-by: Slávek Banko <slavek.banko@axis.cz>

src/progpreferences.ui

@@ -281,12 +281,7 @@ when the applet starts.</string>
     </grid>
 </widget>
 <layoutdefaults spacing="6" margin="11"/>
-<includehints>
-    <includehint>knuminput.h</includehint>
-    <includehint>knuminput.h</includehint>
-    <includehint>knuminput.h</includehint>
-    <includehint>knuminput.h</includehint>
-    <includehint>knuminput.h</includehint>
-    <includehint>knuminput.h</includehint>
-</includehints>
+<includes>
+    <include location="global" impldecl="in implementation">knuminput.h</include>
+</includes>
 </UI>