prservice: remove connection caching

This patch is a follow on of the the PR server rework in bitbake to add
read-only support.  The shift to using the bb.asyncrpc code in the PR
server and client brings issues with respect to reuse of the same
asyncio loop in different processes.  This patch removes the PR service
connection caching to avoid one source of this problem.  It is believed
that in practice this should have little impact on overall performance.

(From OE-Core rev: 0fc3055027e2a76ac863f1c0e0d52e95748066aa)

Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/package.bbclass

@@ -714,9 +714,7 @@ python package_get_auto_pr() {
         return
 
     try:
-        conn = d.getVar("__PRSERV_CONN")
-        if conn is None:
-            conn = oe.prservice.prserv_make_conn(d)
+        conn = oe.prservice.prserv_make_conn(d)
         if conn is not None:
             if "AUTOINC" in pkgv:
                 srcpv = bb.fetch2.get_srcrev(d)
@@ -725,6 +723,7 @@ python package_get_auto_pr() {
                 d.setVar("PRSERV_PV_AUTOINC", str(value))
 
             auto_pr = conn.getPR(version, pkgarch, checksum)
+            conn.close()
     except Exception as e:
         bb.fatal("Can NOT get PRAUTO, exception %s" %  str(e))
     if auto_pr is None: