Fix fd leak on git cmd.

Currently if command is called with as_proces=True, pipes for the
command will not be closed.

This change makes sure to close command file descriptors.

git/cmd.py

@@ -73,6 +73,9 @@ def __init__(self, proc, args ):
 			self.args = args
 
 		def __del__(self):
+			self.proc.stdout.close()
+			self.proc.stderr.close()
+
 			# did the process finish already so we have a return code ?
 			if self.proc.poll() is not None:
 				return
@@ -100,6 +103,8 @@ def wait(self):
 
 			:raise GitCommandError: if the return status is not 0"""
 			status = self.proc.wait()
+			self.proc.stdout.close()
+			self.proc.stderr.close()
 			if status != 0:
 				raise GitCommandError(self.args, status, self.proc.stderr.read())
 			# END status handling