oeqa/runtime/rust: correct rust test

oeqa/runtime/rust: correct rust test

Since setUp of RustCompileTest use cls.tc.copyTo, those tests needs the scp command:

NOTE: ======================================================================
NOTE: FAIL: test_cargo_compile (rust.RustCompileTest)
NOTE: ----------------------------------------------------------------------
NOTE: Traceback (most recent call last):
  File "/home/jenkins/yocto-poky-master/poky/meta/lib/oeqa/core/case.py", line 53, in _oeSetUp
    self.setUpMethod()
  File "/home/jenkins/yocto-poky-master/poky/meta/lib/oeqa/runtime/cases/rust.py", line 17, in setUp
    cls.tc.target.copyTo(src, dst)
  File "/home/jenkins/yocto-poky-master/poky/meta/lib/oeqa/core/target/ssh.py", line 132, in copyTo
    return self._run(scpCmd, ignore_status=False)
  File "/home/jenkins/yocto-poky-master/poky/meta/lib/oeqa/core/target/ssh.py", line 81, in _run
    raise AssertionError("Command '%s' returned non-zero exit "
AssertionError: Command '['scp', '-o', 'ServerAliveCountMax=2', '-o', 'ServerAliveInterval=30', '-o', 'UserKnownHostsFile=/dev/null', '-o', 'StrictHostKeyChecking=no', '-o', 'LogLevel=ERROR', '-r', '-P', '2222', '/home/jenkins/yocto-poky-master/poky/meta/lib/oeqa/files/test.rs', 'root@127.0.0.1:/tmp/']' returned non-zero exit status 1:
sh: scp: not found
lost connection

Signed-off-by: Frederic Martinsons <frederic.martinsons@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>