Add version/host/user headers in sent email

CHANGELOG.md

@@ -5,6 +5,8 @@ and this project **does not adhere to [Semantic Versioning](http://semver.org/sp
 
 ### Added
 
+* version/host/user headers in sent email
+
 ### Changed
 
 ### Deprecated

evomaintenance.sh

@@ -303,6 +303,9 @@ From: ${FULLFROM}
 Content-Type: text/plain; charset=UTF-8
 MIME-Version: 1.0
 Content-Transfer-Encoding: 8bit
+X-Evomaintenance-Version: ${VERSION}
+X-Evomaintenance-Host: ${HOSTNAME_TEXT}
+X-Evomaintenance-User: ${USER}
 To: ${EVOMAINTMAIL}
 Subject: [evomaintenance] Intervention sur ${HOSTNAME_TEXT} (${USER})