Add phosphor-gevent recipe

And make it the default for Phosphor.

Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
Change-Id: I531aa457bcc0fae4d4fff833fb1815a12af53edc
diff --git a/meta-phosphor/conf/distro/include/phosphor-defaults.inc b/meta-phosphor/conf/distro/include/phosphor-defaults.inc
index a99ad66..3cff3f6 100644
--- a/meta-phosphor/conf/distro/include/phosphor-defaults.inc
+++ b/meta-phosphor/conf/distro/include/phosphor-defaults.inc
@@ -7,3 +7,5 @@
 OBMC_POWER_BUTTON_INSTANCES ?= "0"
 OBMC_BMC_INSTANCES ?= "0"
 OBMC_FAN_INSTANCES ?= ""
+
+PREFERRED_PROVIDER_virtual/obmc-wsgihost ?= "phosphor-gevent"