change CentOS 7 to pull from git (#3734)

The package setup for CentOS 7 already installs git so use it for the install. This makes later updates easier for the end users. They can simply use git pull like the instructions say for updating.

snipeit.sh

@@ -446,9 +446,7 @@ case $distro in
 
 		echo -e "\n##  Downloading Snipe-IT from github and put it in the web directory.";
 
-		log "wget -P $tmp/ https://github.com/snipe/snipe-it/archive/$file"
-		log "unzip -qo $tmp/$file -d $tmp/"
-		log "cp -R $tmp/$fileName $webdir/$name"
+		log "git clone https://github.com/snipe/snipe-it $webdir/$name"
 
 		# Make mariaDB start on boot and restart the daemon
 		echo "##  Starting the mariaDB server.";