logtoprocess: fix message formatting
The logtoprocess used to try formatting the message using keyword options
instead of always using the rest of the arguments. Update it to match blackbox
behavior.
Differential Revision: https://phab.mercurial-scm.org/D5180
pager.pager=p0 # $TESTTMP/sysrc:4
ui.editor=e1 # $TESTTMP/userrc:2
pager.pager=p2 # $PAGER
ui.editor=e1 # $TESTTMP/userrc:2