insane/package: let package.bbclass inherit insane.bbclass

RP's comment:
"What we're trying to do is move everything to use a standard mechanism
for reporting issues of this type (do_package). With insane.bbclass, you
can elect whether a given type of error is a warning or error and fails
the task."

* The package.bbclass had used package_qa_handle_error() which is from
  insane.bbclass, and we will use it for handling other warnings and
  errors, so let package.bbclass inherit insane.bbclass, this change will
  make the insane as a requirement (always included).

* Change the "PACKAGEFUNCS ?=" to "+=", otherwise there would be an
  error like:
  Exception: variable SUMMARY references itself!

  This is because we let package.bbclass inherit insane.bbclass, and
  PACKAGEFUNCS has been set in insane.bbclass, so the "PACKAGEFUNCS ?="
  will set nothing, then the "emit_pkgdata" doesn't run which will
  cause this error.

* Add a QA_SANE variable in insane.bbclass, once the error type
  is ERROR_QA, it will fail the task and stop the build.

[YOCTO #3190]
[YOCTO #4396]

(From OE-Core rev: 852dead71387c66ec0cba7c71e3814a74e409560)

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/package.bbclass

@@ -42,6 +42,9 @@ inherit packagedata
 inherit prserv
 inherit chrpath
 
+# Need the package_qa_handle_error() in insane.bbclass
+inherit insane
+
 PKGD    = "${WORKDIR}/package"
 PKGDEST = "${WORKDIR}/packages-split"
 
@@ -1813,7 +1816,7 @@ PACKAGESPLITFUNCS ?= " \
                 package_do_split_locales \
                 populate_packages"
 # Functions which process metadata based on split packages
-PACKAGEFUNCS ?= " \
+PACKAGEFUNCS += " \
                 package_fixsymlinks \
                 package_name_hook \
                 package_do_filedeps \