image.bbclass: The wrong name is being used for the debug filesystem

[YOCTO #9487]

The debug filesystem file name is ending in "debug_tar", it should be simply
"tar".  Strip the "debug_" piece as necessary.

To avoid deleting the tar ball, when we've asked for just the tarball we need
to check 't' and not 'realt'.

The two hunks were suggested by RP.  I've implemented and verify they work
with the settings:

PACKAGE_CLASSES = "package_rpm"
IMAGE_GEN_DEBUGFS = '1'

IMAGE_FSTYPES_DEBUGFS = "tar.bz2"

IMAGE_FSTYPES_DEBUGFS = "tar.gz"

and

IMAGE_FSTYPES_DEBUGFS = "tar"

(From OE-Core rev: ca088bebfc3603ef206b20501916019f0572f955)

Signed-off-by: Mark Hatle <mark.hatle@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/image.bbclass

@@ -393,6 +393,8 @@ python () {
             for ctype in ctypes:
                 if bt.endswith("." + ctype):
                     type = bt[0:-len(ctype) - 1]
+                    if type.startswith("debugfs_"):
+                        type = type[8:]
                     # Create input image first.
                     gen_conversion_cmds(type)
                     localdata.setVar('type', type)
@@ -406,7 +408,7 @@ python () {
             gen_conversion_cmds(bt)
 
         localdata.setVar('type', realt)
-        if realt not in alltypes:
+        if t not in alltypes:
             rm_tmp_images.add(localdata.expand("${IMAGE_NAME}${IMAGE_NAME_SUFFIX}.${type}"))
         else:
             subimages.append(realt)