convert Bazaar and class into methods

[Martin Mrazik]

See this for more context:
https://code.launchpad.net/~mrazik/jenkins-launchpad-plugin/dput-python/+merge/119578

112 +class Bazaar(object):
113 + def _call(self, args):
114 + try:
115 + subprocess.check_call(['bzr', ] + args)
116 + except subprocess.CalledProcessError:
117 + logger.error('Call for bzr ' + str(args) + ' failed')
118 + exit(1)
119 +
120 + def _call_output(self, args):
121 + try:
122 + output = subprocess.check_output(['bzr', ] + args,
123 + stderr=open('/dev/null', 'w'))
124 + return output
125 + except subprocess.CalledProcessError:
126 + logger.error('Call for bzr ' + str(args) + ' failed')
127 + exit(1)
128 +
129 + def whoami(self, who):
130 + self._call(['whoami', who, ])
131 +
132 + def branch(self, branch, target_dir):
133 + self._call(['branch', branch, target_dir])
134 +
135 + def revert(self, target_dir):
136 + self._call(['revert', target_dir])
137 +
138 + def merge(self, branch):
139 + self._call(['merge', branch])
140 +
141 + def build(self, recipe, target):
142 + self._call(['build', recipe, target])
143 +
144 + def revno(self, target):
145 + return int(self._call_output(['revno', target]).strip())

As thomi mentioned, this doesn't need to be a class. Comment only, hope you add it to your TODO :-)