Revert "Add keep-alive option in webpack devServer"

This reverts commit bf37b317496c80dc9a87f49356efdab8a3b50caa.

The current version of the stack doesn't prevent logging in and all
operations without overriding "Connection:" header.

This overriding is making it impossible to test any WebSocket-based
functionality (IP KVM, SOL, Virtual Media).

Tested: logging in, navigating the interface, using IP KVM and SOL
console.

Fixes: https://github.com/openbmc/webui-vue/issues/94
Change-Id: I6174c75e35784ff370f6adf7841c98ae78a26ceb
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
diff --git a/vue.config.js b/vue.config.js
index c1dd2ec..38b4be9 100644
--- a/vue.config.js
+++ b/vue.config.js
@@ -43,9 +43,6 @@
     proxy: {
       '/': {
         target: process.env.BASE_URL,
-        headers: {
-          Connection: 'keep-alive',
-        },
         onProxyRes: (proxyRes) => {
           // This header is ignored in the browser so removing
           // it so we don't see warnings in the browser console