BUG/MINOR: server: check for either proxy-protocol v1 or v2 to send hedaer

BUG/MINOR: server: check for either proxy-protocol v1 or v2 to send hedaer

As reported in issue #2882, using "no-send-proxy-v2" on a server line does
not properly disable the use of proxy-protocol if it was enabled in a
default-server directive in combination with other PP options. The reason
for this is that the sending of a proxy header is determined by a test on
srv->pp_opts without any distinction, so disabling PPv2 while leaving other
options results in a PPv1 header to be sent.

Let's fix this by explicitly testing for the presence of either send-proxy
or send-proxy-v2 when deciding to send a proxy header.

This can be backported to all versions. Thanks to Andre Sencioles (@asenci)
for reporting the issue and testing the fix.