Fix "svn commit --force" example to actually specify "--force".  
Fix "svn commit --force" example to actually specify "--force".  

Patch by: Julian Foad <julianfoad@btopenworld.com>

* doc/book/book/ch08.xml
  Specify "--force" in the example use of "--force".

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion