utils/test-pkg: remove configurations that are skipped

When the config fragment provided by the user is not usable with a
specific toolchain configuration, the resulting .config file was kept
around.

In a follow up commit, we'll need to know, from outside test-pkg, if a
specific configuration was indeed usable or not.

So, unless if the user actually requested to keep the build directories,
remove the .config file when it contains a configration that would be
skipped.

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Cc: Romain Naour <romain.naour@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

utils/test-pkg

@@ -161,6 +161,10 @@ build_one() {
     # done in the same locale.
     comm -23 <(sort "${cfg}") <(sort "${dir}/.config") >"${dir}/missing.config"
     if [ -s "${dir}/missing.config" ]; then
+        if [ ${keep} -ne 1 ]; then
+            # Invalid configuration, drop it
+            rm -f "${dir}/.config"
+        fi
         return 1
     fi
     # Remove file, it's empty anyway.