Fix init -d behaviour when master branch exists, and one or more othe…

…r branch exists, but develop does not

Without this change, init picks 'master' as both the production and integration branch and fails. With it, init detects the clash and behaves the same as if only master exists, picking 'develop' as integration branch

git-flow-init

@@ -153,11 +153,17 @@ cmd_default() {
 			default_suggestion=
 			for guess in $(git config --get gitflow.branch.develop) \
 			             'develop' 'int' 'integration' 'master'; do
-				if git_local_branch_exists "$guess"; then
+				if git_local_branch_exists "$guess" && [ "$guess" != "$master_branch" ]; then
 					default_suggestion="$guess"
 					break
 				fi
 			done
+
+			if [ -z $default_suggestion ]; then
+				should_check_existence=NO
+				default_suggestion=$(git config --get gitflow.branch.develop || echo develop)
+			fi
+
 		fi
 
 		printf "Branch name for \"next release\" development: [$default_suggestion] "