Do not force SYNC

It might be preferrable from a consistency standpoint,
but many CLI tests start failing when you force this.

So, as the previous behaviour was not forcing the sync, this seems
to show there could be unintended behavioural changes in effect.

Possibly, we'll want to address this later, but as the main goal
here was to make commit() atomic as much as possible, fixing
this is probably another story anyway.

Note: I was *never* able to reproduce those failures on my machine in
a normal env dev. It was only visible in CI.
I finally managed to make it reproducible (but still a bit randomly) by
using Docker resource constraints, using something like this:

* cd to jenkins local clone
* `docker run -ti -v m2repo:/root/.m2/repository -v $PWD:/work -v ~/.m2/settings.xml:/root/.m2/settings.xml:ro -v ~/.m2/settings-security.xml:/root/.m2/settings-security.xml:ro --device-write-iops /dev/mapper/fedora-home:40 --device-read-iops /dev/mapper/fedora-home:40  --device-write-bps /dev/mapper/fedora-home:10m --device-read-bps /dev/mapper/fedora-home:10m maven:3.5.2-jdk-8 bash`
* cd /work
* `mvn clean install -Dtest=WaitNodeOfflineCommandTest,RunRangeCommandTest -Dfindbugs.skip=true  -DfailIfNoTests=false -Dskip.npm=true`

Failure example:

```
ERROR] Tests run: 6, Failures: 2, Errors: 0, Skipped: 0, Time elapsed: 55.68OfflineCommandTest
[ERROR] waitNodeOfflineShouldSucceedOnDisconnectingNode(hudson.cli.WaitNodeOf  <<< FAILURE!
java.lang.AssertionError:

Expected: <true>
     but: was <false>
        at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:20)
        at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:8)
        at hudson.cli.WaitNodeOfflineCommandTest.waitNodeOfflineShouldSucceedndTest.java:128)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorIm
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAc
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(Framew
        at org.junit.internal.runners.model.ReflectiveCallable.run(Reflective
        at org.junit.runners.model.FrameworkMethod.invokeExplosively(Framewor
        at org.junit.internal.runners.statements.InvokeMethod.evaluate(Invoke
        at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefor
        at org.jvnet.hudson.test.JenkinsRule$1.evaluate(JenkinsRule.java:542)
        at org.junit.internal.runners.statements.FailOnTimeout$CallableStatem
        at org.junit.internal.runners.statements.FailOnTimeout$CallableStatem
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.lang.Thread.run(Thread.java:748)

[ERROR] waitNodeOfflineShouldSucceedOnDisconnectedNode(hudson.cli.WaitNodeOff <<< FAILURE!
java.lang.AssertionError
```