verify_certs: check and error when manifest is missing, because for some dumb reason jarsigner think it's okay

conf/resdl-download.txt

@@ -139,7 +139,7 @@ verifycerts() {
 
   for repo in $(echo "$stuff_repo" | select_word 1); do
     certobject="repo/$repo.cer";
-    jarsigner -verify "$tmpdir/repos/$repo.jar" > /dev/null || {
+    unzip -l "$tmpdir/repos/$repo.jar" "META-INF/*" | grep -q "META-INF/MANIFEST.MF" && jarsigner -verify "$tmpdir/repos/$repo.jar" > /dev/null || {
       echo "  !! Verification failed for repo ($repo)" >&2;
       continue;
     }
@@ -161,7 +161,7 @@ verifycerts() {
 
   for object in $(echo "$stuff_download" | grep -E "^[ ]*[^ ]+.apk[ ]+" | select_word 1); do
     certobject="$(dirname "$object")/$(basename "$object" .apk).cer";
-    jarsigner -verify "$resdldir/$object" > /dev/null || {
+    unzip -l "$resdldir/$object" "META-INF/*" | grep -q "META-INF/MANIFEST.MF" && jarsigner -verify "$resdldir/$object" > /dev/null || {
       echo "  !! Verification failed for APK ($object)" >&2;
       continue;
     }