ITS#9511 - Stop plugin.c from generating an error when running make depend...

ITS#9511 - Stop plugin.c from generating an error when running make depend even if slapi is not enabled
3 jobs for !313 with its9511 in 46 minutes and 18 seconds (queued for 26 seconds)
latest detached
Status Job ID Name Coverage
  Build
passed #6166
build-gnutls-mit-standalone-lloadd

00:44:39

passed #6164
build-no-threads-no-slapd

00:02:44

passed #6165
build-openssl-heimdal-lloadd

00:46:17