__git_ps1 issue in v1.7.10.1

[GoogleCodeExporter]

What steps will reproduce the problem?
1. I have "$(__git_ps1 '(%s)')" within my PS1 being set in my .bash_profile so 
that I can see the dirty and untracked file state of repositories I'm in on the 
terminal.
2. Upgrading to v1.7.10.1 caused it suddenly to take ~13seconds when inside of 
a directory with a .git directory to re-render the prompt.

What is the expected output? What do you see instead?
The prompt to appear immediately.

What version of the product are you using? On what operating system?
v1.7.10.1 on os x (haven't tested on my linux machine yet).  This problem was 
not occurring with v1.7.10

Please provide any additional information below.

Original issue reported on code.google.com by gjast...@gmail.com on 3 May 2012 at 9:32