mongo: testEnsureNumaCtl fails when $TMPDIR is set

[Roger Peppe]

This assertion can fail because the temp dir does not necessarily
match the asserted pattern.

Also, FWIW, there is no point in having the '($MULTI_NODE)' pattern
there - it can never match (because the $ is not escaped) and
the ?.* after it means that it is irrelevant whether it matches or not.

Example failure.

 ----------------------------------------------------------------------
 FAIL: mongo_test.go:202: MongoSuite.TestEnsureServer

 [LOG] 0:00.000 INFO juju.mongo Ensuring mongo server is running; data directory /tmp/alesstimec/check-4990765271833742716/15; port 25252
 [LOG] 0:00.000 INFO juju.mongo installing juju-mongodb
 [LOG] 0:00.000 INFO juju.utils.packaging.manager Running: apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install juju-mongodb
 [LOG] 0:00.095 DEBUG juju.mongo using mongod: /tmp/alesstimec/check-4990765271833742716/13/mongod --version: "db version v2.4.9"
 mongo_test.go:203:
     dataDir := s.testEnsureServerNumaCtl(c, false)
 mongo_test.go:315:
     c.Assert(service.Conf().ExecStart, gc.Matches, `($MULTI_NODE)?.*tmp/check-.*/mongod.*`)
 ... value string = "/tmp/alesstimec/check-4990765271833742716/13/mongod --auth --dbpath '/tmp/alesstimec/check-4990765271833742716/15/db' --sslOnNormalPorts --sslPEMKeyFile '/tmp/alesstimec/check-4990765271833742716/15/server.pem' --sslPEMKeyPassword ignored --port 25252 --noprealloc --syslog --smallfiles --journal --keyFile '/tmp/alesstimec/check-4990765271833742716/15/shared-secret' --replSet juju --ipv6 --oplogSize 1"
 ... regex string = "($MULTI_NODE)?.*tmp/check-.*/mongod.*"

 ----------------------------------------------------------------------
 FAIL: mongo_test.go:283: MongoSuite.TestEnsureServerNumaCtl

 [LOG] 0:00.000 INFO juju.mongo Ensuring mongo server is running; data directory /tmp/alesstimec/check-4990765271833742716/19; port 25252
 [LOG] 0:00.000 INFO juju.mongo installing juju-mongodb and numactl
 [LOG] 0:00.000 INFO juju.utils.packaging.manager Running: apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install juju-mongodb
 [LOG] 0:00.050 INFO juju.utils.packaging.manager Running: apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install numactl
 [LOG] 0:00.093 DEBUG juju.mongo using mongod: /tmp/alesstimec/check-4990765271833742716/17/mongod --version: "db version v2.4.9"
 mongo_test.go:284:
     s.testEnsureServerNumaCtl(c, true)
 mongo_test.go:315:
     c.Assert(service.Conf().ExecStart, gc.Matches, `($MULTI_NODE)?.*tmp/check-.*/mongod.*`)
 ... value string = "$MULTI_NODE/tmp/alesstimec/check-4990765271833742716/17/mongod --auth --dbpath '/tmp/alesstimec/check-4990765271833742716/19/db' --sslOnNormalPorts --sslPEMKeyFile '/tmp/alesstimec/check-4990765271833742716/19/server.pem' --sslPEMKeyPassword ignored --port 25252 --noprealloc --syslog --smallfiles --journal --keyFile '/tmp/alesstimec/check-4990765271833742716/19/shared-secret' --replSet juju --ipv6 --oplogSize 1"
 ... regex string = "($MULTI_NODE)?.*tmp/check-.*/mongod.*"

 OOPS: 49 passed, 2 FAILED
 --- FAIL: Test (10.66s)
 FAIL
 FAIL github.com/juju/juju/mongo 10.797s