Bug in --status regex

[jedwards4b]

Summary of Issue: The RE_TRACKING reg ex in repository_git.py appears to be too restrictive.

Expected behavior and actual behavior:I have a clm checkout that looks like

git status
On branch pio2_cleanup
Your branch and 'mydev/pio2_cleanup' have diverged,
and have 62 and 2 different commits each, respectively.
  (use "git pull" to merge the remote branch into yours)

Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)

	modified:   src/main/ncdio_pio.F90.in

no changes added to commit (use "git add" and/or "git commit -a")

Current behavior is:

Processing externals description file : Externals.cfg
Processing externals description file : Externals_CLM.cfg
Processing externals description file : Externals_POP.cfg
Processing externals description file : Externals_CISM.cfg
Checking status of externals: clm, 
ERROR: DEV_ERROR: regex to detect tracking branch failed.

If I changes the RE_TRACKING to be RE_TRACKING = re.compile(r'[(.+)]')
then I get what I think that I should expect:

Processing externals description file : Externals.cfg
Processing externals description file : Externals_CLM.cfg
Processing externals description file : Externals_POP.cfg
Processing externals description file : Externals_CISM.cfg
Checking status of externals: clm, fates, ptclm, mosart, ww3, cime, cice, pop, cvmix, marbl, cism, source_cism, rtm, cam, 
sM  ./cime
        modified sandbox, cesmdev/master: ahead 136 --> cime5.4.0-alpha.23
 M  ./components/cam
        modified sandbox, on cam1/trunk_tags/cam5_4_166/components/cam
s   ./components/cice
        clean sandbox, origin/master --> cice5_20180123
    ./components/cism
        clean sandbox, on cism2_1_46
    ./components/cism/glimmer-cism
        clean sandbox, on test_coupling_move_up_v2_n01
sM  ./components/clm
        modified sandbox, mydev/pio2_cleanup: ahead 62, behind 2 --> clm5.0.dev001
    ./components/clm/src/fates
        clean sandbox, on fates_s1.4.1_a3.0.0_rev3
s   ./components/clm/tools/PTCLM
        clean sandbox, PTCLM2_171216c --> PTCLM2_180214
    ./components/mosart
        clean sandbox, on mosart1_0_30
    ./components/pop
        clean sandbox, on pop2/trunk_tags/cesm_pop_2_1_20180205
    ./components/pop/externals/CVMix
        clean sandbox, on v0.72-conv_bugfix.002
    ./components/pop/externals/MARBL
        clean sandbox, on MARBL/trunk_tags/MARBL0_22_0
    ./components/rtm
        clean sandbox, on rtm1_0_65
    ./components/ww3
        clean sandbox, on ww3/trunk_tags/ww3_180115

Steps to reproduce the problem. Include externals description file(s) and link to public repository):

What is the changeset ID of the code, and the machine you are using:

have you modified the code? If so, it must be committed and available for testing:

Screen output or log file showing the error message and context:

[billsacks]

This issue was moved to ESMCI/manage_externals#71