Skipping dockerignore files in version check scripts

Change-Id: I694b55d7feb7e15991906a587ff106a32ecca6cb
diff --git a/jjb/shell/tagcollisionreject.sh b/jjb/shell/tagcollisionreject.sh
index 309e35c..a7ba04e 100755
--- a/jjb/shell/tagcollisionreject.sh
+++ b/jjb/shell/tagcollisionreject.sh
@@ -140,7 +140,7 @@
 
     done
 
-  done  < <( find "${WORKSPACE}" -name 'Dockerfile*' ! -path "*/vendor/*" -print0 )
+  done  < <( find "${WORKSPACE}" -name 'Dockerfile*' ! -path "*/vendor/*" ! -name "*dockerignore" -print0 )
 }
 
 echo "Checking git repo with remotes:"