devel/p5-SVN-Access: Don't strip scripts

The strip program from new binutils will complain if one tries to strip
executables non-binaries. The INSTALL_PROGRAM macro tries to strip; for
a perl script the INSTALL_SCRIPT macro is the correct one to use.

Swapping the macros fixes this error:

/usr/libexec/binutils224/elf/strip:
  /wrkdirs/devel/p5-SVN-Access/work/stage/usr/local/share/examples/
  SVN-Access/svnaclmgr.pl: File format not recognized

Approved by: just-fix-it blanket