No functional changes intended.
Previously the library names of rlibs sometimes had two dashes, like
libslib--389267823.rlib.  This happens because the hash() function may
return a negative value, so the second dash is the minus sign. However
such names are a bit confusing since they look like there's a missing
component between the two dashes that didn't get properly propagated,
which is not true.
For the unit test, since the hash() function is the standard Java String hashCode
function, I chose "slib"  since that produces a negative hash code.