[FIXED HUDSON-2341] Colored ball image at top of build pages was broken

for Hudson in some web containers. Fixed by removing workaround (r323)
for a Firefox bug (https://bugzilla.mozilla.org/show_bug.cgi?id=89419),
fixed since 3.0.5 (Dec, 2008).


git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@29855 71c3de6d-444a-0410-be80-ed276b4c234a