git-gui: relax "dirty" version detection

"git gui" would complain at launch if the local version of Git was
"1.5.4.2.dirty". Loosen the regular expression to look for either
"-dirty" or ".dirty", thus eliminating spurious warnings.

Signed-off-by: Wincent Colaiuta <win@wincent.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

git-gui.sh

@@ -662,7 +662,7 @@ if {![regsub {^git version } $_git_version {} _git_version]} {
 }
 
 set _real_git_version $_git_version
-regsub -- {-dirty$} $_git_version {} _git_version
+regsub -- {[\-\.]dirty$} $_git_version {} _git_version
 regsub {\.[0-9]+\.g[0-9a-f]+$} $_git_version {} _git_version
 regsub {\.rc[0-9]+$} $_git_version {} _git_version
 regsub {\.GIT$} $_git_version {} _git_version