No. There is more to this issue than just the ignored files.
Here's a test case from a simple Jenkins / SVN (Jenkins 1.483, SVN 1.7):
After wiping out the workspace and running an initial build:
[root@devemr01 UTIL_TRUNK]# ll
total 24
drwxrwxr-x 10 jenkins jenkins 4096 Sep 30 00:06 build
-rw-rw-r-- 1 jenkins jenkins 376 Sep 30 00:06 build.gradle
drwxrwxr-x 2 jenkins jenkins 4096 Sep 30 00:06 lib
drwxrwxr-x 2 jenkins jenkins 4096 Sep 30 00:06 releng
-rw-rw-r-- 1 jenkins jenkins 37 Sep 30 00:06 settings.gradle
drwxrwxr-x 4 jenkins jenkins 4096 Sep 30 00:06 src
...adding an unversioned file:
[root@devemr01 UTIL_TRUNK]# touch foo
[root@devemr01 UTIL_TRUNK]# svn status
? foo
Running the job (note that the unversioned file wasn't detected or removed):
00:07:59 Cleaning up /home/jenkins/workspace/UTIL_TRUNK/.
00:07:59 Updating svn:00:07:59 At revision 38394
...and the unversioned file, and the ignored dir 'build', are still present:
[root@devemr01 UTIL_TRUNK]# ll
total 24
drwxrwxr-x 10 jenkins jenkins 4096 Sep 30 00:06 build
-rw-rw-r-- 1 jenkins jenkins 376 Sep 30 00:06 build.gradle
-rw-r--r-- 1 root root 0 Sep 30 00:07 foo
drwxrwxr-x 2 jenkins jenkins 4096 Sep 30 00:06 lib
drwxrwxr-x 2 jenkins jenkins 4096 Sep 30 00:06 releng
-rw-rw-r-- 1 jenkins jenkins 37 Sep 30 00:06 settings.gradle
drwxrwxr-x 4 jenkins jenkins 4096 Sep 30 00:06 src
[root@devemr01 UTIL_TRUNK]#
It appears that the SVNKit 'status' API call is working differently (and possibly incorrectly) for SVN 1.7 repositories.
Does this explain not deleting unversioned files as well? Because you're mentioning only ignored files...