Added function gitflow_require_initialized(), to assert that the gitflow
variables are all set (they need to be set explicitly once).
diff --git a/git-flow-feature b/git-flow-feature
index 701ed6b..d005648 100644
--- a/git-flow-feature
+++ b/git-flow-feature
@@ -13,8 +13,9 @@
 #
 
 gitflow_require_git_repo
+gitflow_require_initialized
 gitflow_load_settings
-PREFIX=$(git config --get gitflow.prefix.feature || echo feature/)
+PREFIX=$(git config --get gitflow.prefix.feature)
 
 usage() {
 	echo "usage: git flow feature [list] [-v]"