* autogen.sh: Make purging of build .pyc files conditional on release mode,     and make non-verbose.
* autogen.sh: Make purging of build .pyc files conditional on release mode,
    and make non-verbose.

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