reset upstream subtrees to yocto 2.6

Reset the following subtrees on thud HEAD:

  poky: 87e3a9739d
  meta-openembedded: 6094ae18c8
  meta-security: 31dc4e7532
  meta-raspberrypi: a48743dc36
  meta-xilinx: c42016e2e6

Also re-apply backports that didn't make it into thud:
  poky:
    17726d0 systemd-systemctl-native: handle Install wildcards

  meta-openembedded:
    4321a5d libtinyxml2: update to 7.0.1
    042f0a3 libcereal: Add native and nativesdk classes
    e23284f libcereal: Allow empty package
    030e8d4 rsyslog: curl-less build with fmhttp PACKAGECONFIG
    179a1b9 gtest: update to 1.8.1

Squashed OpenBMC subtree compatibility updates:
  meta-aspeed:
    Brad Bishop (1):
          aspeed: add yocto 2.6 compatibility

  meta-ibm:
    Brad Bishop (1):
          ibm: prepare for yocto 2.6

  meta-ingrasys:
    Brad Bishop (1):
          ingrasys: set layer compatibility to yocto 2.6

  meta-openpower:
    Brad Bishop (1):
          openpower: set layer compatibility to yocto 2.6

  meta-phosphor:
    Brad Bishop (3):
          phosphor: set layer compatibility to thud
          phosphor: libgpg-error: drop patches
          phosphor: react to fitimage artifact rename

    Ed Tanous (4):
          Dropbear: upgrade options for latest upgrade
          yocto2.6: update openssl options
          busybox: remove upstream watchdog patch
          systemd: Rebase CONFIG_CGROUP_BPF patch

Change-Id: I7b1fe71cca880d0372a82d94b5fd785323e3a9e7
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/poky/bitbake/lib/bb/fetch2/perforce.py b/poky/bitbake/lib/bb/fetch2/perforce.py
index 3debad5..903a8e6 100644
--- a/poky/bitbake/lib/bb/fetch2/perforce.py
+++ b/poky/bitbake/lib/bb/fetch2/perforce.py
@@ -43,13 +43,9 @@
         provided by the env, use it.  If P4PORT is specified by the recipe, use
         its values, which may override the settings in P4CONFIG.
         """
-        ud.basecmd = d.getVar('FETCHCMD_p4')
-        if not ud.basecmd:
-            ud.basecmd = "/usr/bin/env p4"
+        ud.basecmd = d.getVar("FETCHCMD_p4") or "/usr/bin/env p4"
 
-        ud.dldir = d.getVar('P4DIR')
-        if not ud.dldir:
-            ud.dldir = '%s/%s' % (d.getVar('DL_DIR'), 'p4')
+        ud.dldir = d.getVar("P4DIR") or (d.getVar("DL_DIR") + "/p4")
 
         path = ud.url.split('://')[1]
         path = path.split(';')[0]