Fix Bug1672 - Display garbage value on LE machine for BE data.
Description:
Casuing by calling diff_dataset twice when -r or no option was given.
Change to call it once which fix the problem.
It also improves the performance. (diffing time in half)
According further test, it also occurred on BE machine as well and it
seems occruing only with the BE data attached to Bugzilla.
Don't know how the file was created. Anyway this fix will prevent
from diffing with garbage values in similiar potential case.
Tested on:
linux32 (jam) , linux64 (almani), solaris (linew)
