Ensure we sanitize branch names with path-unfriendly characters

Signed-off-by: Rémy Coutable <remy@rymai.me>

lib/gitlab/ee_compat_check.rb

@@ -149,7 +149,7 @@ module Gitlab
     end
 
     def ce_patch_name
-      @ce_patch_name ||= "#{ce_branch}.patch"
+      @ce_patch_name ||= patch_name_from_branch(ce_branch)
     end
 
     def ce_patch_full_path
@@ -161,13 +161,17 @@ module Gitlab
     end
 
     def ee_patch_name
-      @ee_patch_name ||= "#{ee_branch}.patch"
+      @ee_patch_name ||= patch_name_from_branch(ee_branch)
     end
 
     def ee_patch_full_path
       @ee_patch_full_path ||= patches_dir.join(ee_patch_name)
     end
 
+    def patch_name_from_branch(branch_name)
+      branch_name.parameterize << '.patch'
+    end
+
     def step(desc, cmd = nil)
       puts "\n=> #{desc}\n"