DeprecationWarning for popen3 in hg_sage

[wjp]

Using hg_sage is raising a DeprecationWarning:

/data/sage/sage-4.3.1.rc0/local/lib/python2.6/site-packages/sage/misc/hg.py:240: DeprecationWarning: os.popen3 is deprecated.  Use the subprocess module.
  x = os.popen3(s)

Component: misc

Author: Willem Jan Palenstijn

Reviewer: Tim Dumol

Merged: sage-4.3.1.rc1

Issue created by migration from https://trac.sagemath.org/ticket/7967

[TimDumol]

Reviewer: Tim Dumol

[TimDumol]

Author: Willem Palenstijn

[TimDumol]

comment:2

Attachment: 7967_popen3.patch.gz

Good job; looks good.

[rlmill]

Merged: sage-4.3.1.rc1

[fchapoton]

Changed author from Willem Palenstijn to Willem Jan Palenstijn