packaging: setup: updated early statement for /api

The current proxy configuration removes Expect
headers incorrectly:

1) The 'early' statement removed by the commit
4acbcb524 is still required.

2) According to mod_headers documentation at [1],
the directive cannot be used as nested in <Location>:

"Because early directives are processed before the request
path's configuration is traversed, early headers can only
be set in a main server or virtual host context.
 Early directives cannot depend on a request path, so they
will fail in contexts such as <Directory> or <Location>"

The new implementation brings back the 'early' directive and
relocates the statement into main context.

[1] http://httpd.apache.org/docs/current/mod/mod_headers.html

Change-Id: I4dda234b7669dcd6c6eb76728a8536ba49247393
Bug-Url: https://bugzilla.redhat.com/849442
Related-To: https://bugzilla.redhat.com/979737
Signed-off-by: Alex Lourie <alourie@redhat.com>