slaprunner: do not try to chdir if not a directory while building exclude list

If instance/slappartXX is not a folder but file, skip chdir else import/export fail with a message like:

    /srv/slapgrid/slappart18/bin/runner-exporter run at : Thu Oct  4 04:30:03 CEST 2018
    Traceback (most recent call last):
      File "<stdin>", line 17, in <module>
    OSError: [Errno 20] Not a directory: '/srv/slapgrid/slappart18/srv//runner/instance/slappart5-mariadb.dump.sql.gz'

software/slaprunner/buildout.hash.cfg

@@ -22,7 +22,7 @@ md5sum = e12255a8c946b3eb8c6373fff481339f
 
 [template-runner-import-script]
 filename = template/runner-import.sh.jinja2
-md5sum = 92ac3f6982dec97e3b2df90f97111bd3
+md5sum = bdfcf6edc20cc9f390b3e34e2531377b
 
 [instance-runner-import]
 filename = instance-runner-import.cfg.in
@@ -30,7 +30,7 @@ md5sum = 7a879739afe55320ee96409bcc8a52ab
 
 [template-runner-export-script]
 filename = template/runner-export.sh.jinja2
-md5sum = d9b110db2a35c88c9eb8f87c2d2cad21
+md5sum = be47acbe610305982168cff6a9eeb9ec
 
 [instance-runner-export]
 filename = instance-runner-export.cfg.in

software/slaprunner/template/runner-export.sh.jinja2

@@ -56,7 +56,12 @@ if 1:
         print("*.pid")
         print(".installed*.cfg")
         for partition in glob.glob(path + "/instance/slappart*"):
+            try:
               os.chdir(partition)
+            except OSError as e:
+              if e.errno != errno.ENOTDIR:
+                raise
+              continue
             try:
                 with open("srv/exporter.exclude") as f:
                     exclude = f.readlines()

software/slaprunner/template/runner-import.sh.jinja2

@@ -69,7 +69,12 @@ if 1:
         print("*.pid")
         print(".installed*.cfg")
         for partition in glob.glob(path + "/instance/slappart*"):
+            try:
               os.chdir(partition)
+            except OSError as e:
+              if e.errno != errno.ENOTDIR:
+                raise
+              continue
             try:
                 with open("srv/exporter.exclude") as f:
                     exclude = f.readlines()