[Bug-tar] make clean bug in CVS head

[Eric Blake]

A fresh CVS checkout, followed by ./bootstrap; ./configure; make clean, 
unnecessarily fails with:

$ make clean
Making clean in tests
make[1]: Entering directory `/home/eblake/tar/tests'
test -z "genfile.exe" || rm -f genfile.exe
/bin/sh ./testsuite --clean
/bin/sh: ./testsuite: No such file or directory
make[1]: *** [clean-local] Error 127
make[1]: Leaving directory `/home/eblake/tar/tests'
make: *** [clean-recursive] Error 1

This should be more robust to the testsuite not existing (which is the case if 
I haven't run 'make check' since the last time I cleaned up), especially since 
this error prevents other directories from being cleaned.

--
Eric Blake