Description of problem:
Python module bkr.client is lacking support for 'like' operator as described in docs[1][2]. I'd quite need this operator to be supported.

[1] http://beaker-project.org/docs/user-guide/job-xml.html#job-xml
[2] http://beaker-project.org/schema/beaker-job.rng

Version-Release number of selected component (if applicable):
beaker-client-0.14.1-1.fc18.noarch

How reproducible:
100%

Steps to Reproduce:
bkr workflow-tomorrow 6.4 x86_64 Server --dryrun --hostrequire 'devicelikeipmi'

Actual results:
No task selected, just reserving the machine
Using distro rhel-6.4 from the command line
Traceback (most recent call last):
  File "/bin/bkr", line 9, in <module>
    load_entry_point('bkr.client==0.14.1', 'console_scripts', 'bkr')()
  File "/usr/lib/python2.7/site-packages/bkr/client/main.py", line 50, in main
    return cmd.run(*cmd_args, **cmd_opts.__dict__)
  File "/usr/lib/python2.7/site-packages/bkr/client/commands/cmd_workflow_tomorrow.py", line 1829, in run
    cases=[nitrate.TestCase(id) for id in options.cases])
  File "/usr/lib/python2.7/site-packages/bkr/client/commands/cmd_workflow_tomorrow.py", line 1371, in schedule
    self.check_environment()
  File "/usr/lib/python2.7/site-packages/bkr/client/commands/cmd_workflow_tomorrow.py", line 749, in check_environment
    self.create_recipe(distro, variant, arch))
  File "/usr/lib/python2.7/site-packages/bkr/client/commands/cmd_workflow_tomorrow.py", line 1017, in create_recipe
    recipe.addBaseRequires(**kwargs)
  File "/usr/lib/python2.7/site-packages/bkr/client/__init__.py", line 634, in addBaseRequires
    key, op, value = p2.split(require,3)
ValueError: need more than 1 value to unpack

Expected results:
. . .
			<hostRequires>
				<and>
					<device op="like" value="ipmi"/>
				</and>
			</hostRequires>
. . .

Additional info:
The regex p2 obviously does not accept 'like' operator see
/usr/lib/python2.7/site-packages/bkr/client/__init__.py:
. . .
    625         p2 = re.compile(r'([\!=<>]+|&gt;|&lt;)')
    626         for keyvalue in keyvalues:
    627             key, op, value = p2.split(keyvalue,3)
    628             mykeyvalue = self.doc.createElement('key_value')
    629             mykeyvalue.setAttribute('key', '%s' % key)
    630             mykeyvalue.setAttribute('op', '%s' % op)
    631             mykeyvalue.setAttribute('value', '%s' % value)
    632             self.addHostRequires(mykeyvalue)
    633         for require in requires:
    634             key, op, value = p2.split(require,3)
    635             myrequire = self.doc.createElement('%s' % key)
    636             myrequire.setAttribute('op', '%s' % op)
    637             myrequire.setAttribute('value', '%s' % value)
    638             self.addHostRequires(myrequire)
. . .