create directory if it doesn't exist

src/freedombone

@@ -6631,6 +6631,10 @@ function install_owncloud_official_deb {
     # get the official owncloud deb package. Note that this is not the same as the one
     # from the debian repos, and doesn't follow the debian packaging guidelines
+    if [ ! -d $INSTALL_DIR ]; then
+        mkdir $INSTALL_DIR
+    fi
+
     cd $INSTALL_DIR
     wget -nv https://download.owncloud.org/download/repositories/stable/Debian_8.0/Release.key -O owncloud.key
     apt-key add - < owncloud.key