travis: make distcheck scan for BOM markers

and remove BOM from projects/wolfssl_override.props

Closes #3126

.travis.yml

@@ -320,6 +320,8 @@ script:
     - |
         set -eo pipefail
         if [ "$T" = "distcheck" ]; then
+            # find BOM markers and exit if we do
+            ! git grep `printf '\xef\xbb\xbf'`
             ./configure
             make
             ./maketgz 99.98.97

projects/wolfssl_override.props

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <!--
 We use this file to override some properties of the wolfSSL project files.