remove sh/pbs dependency

sh doesn't work on Windows and pbs is no longer supported and doesn't
work on Python 3

Author: spderosso

gitless/cli/gl.py

@@ -13,10 +13,7 @@
 import traceback
 import pygit2
 
-if sys.platform != 'win32':
-  from sh import ErrorReturnCode
-else:
-  from pbs import ErrorReturnCode
+from subprocess import CalledProcessError
 
 from gitless import core
 
@@ -124,7 +121,7 @@ def main():
   except (ValueError, pygit2.GitError, core.GlError) as e:
     pprint.err(e)
     return ERRORS_FOUND
-  except ErrorReturnCode as e:
+  except CalledProcessError as e:
     pprint.err(e.stderr)
     return ERRORS_FOUND
   except:

gitless/cli/gl_commit.py

@@ -7,15 +7,6 @@
 
 from __future__ import unicode_literals
 
-import subprocess
-
-import sys
-if sys.platform != 'win32':
-  from sh import git
-else:
-  from pbs import Command
-  git = Command('git')
-
 from gitless import core
 
 from . import commit_dialog
@@ -74,7 +65,7 @@ def main(args, repo):
   msg = args.m if args.m else commit_dialog.show(commit_files, repo)
   if not msg.strip():
     if partials:
-      git.reset('HEAD', partials)
+      core.git('reset', 'HEAD', partials)
     raise ValueError('Missing commit message')
 
   _auto_track(commit_files, curr_b)
@@ -121,7 +112,7 @@ def _do_partial_selection(files, curr_b):
       pprint.warn('Can\'t select segments for deleted file {0}'.format(fp))
       continue
 
-    subprocess.call(['git', 'add', '-p', fp])
+    core.git('add', '-p', fp)
     # TODO: check that at least one hunk was staged
     partials.append(fp)