Update anki.spec

Signed-off-by: madomado <[email protected]>

anda/apps/anki/anki.spec

@@ -20,6 +20,7 @@ phrases in a foreign language) as easily, quickly and efficiently as possible.
 Anki is based on a theory called spaced repetition.
 
 %prep
+rm -rf *
 git clone https://github.com/ankitects/anki .
 git checkout %{version}
 %patch 0 -p1