DOC: remove last occurrences of "HA-Proxy" syntax

There were only a few more used as output examples and comments in a few
docs, it was the right moment to get rid of them. The file intro.txt
which explains how to parse the version also got a hint about the possible
presence of a hyphen in the name in older versions.
diff --git a/examples/haproxy.init b/examples/haproxy.init
index f08fcb0..cc120d8 100644
--- a/examples/haproxy.init
+++ b/examples/haproxy.init
@@ -1,7 +1,7 @@
 #!/bin/sh
 #
 # chkconfig: - 85 15
-# description: HA-Proxy is a TCP/HTTP reverse proxy which is particularly suited \
+# description: HAProxy is a TCP/HTTP reverse proxy which is particularly suited \
 #              for high availability environments.
 # processname: haproxy
 # config: /etc/haproxy/haproxy.cfg