Bugfix in IvyResolve.
Bugfix in IvyResolve.

Consider a set of targets A, a superset A', and some other set B.

Building A' resolves for A', and then building B resolves for B. If you
then try to run something from A, nothing in it is invalid, and previously
this meant that we wouldn't re-resolve, and instead try to symlink to the
classpath file from a previous compile of A. Except that there isn't one,
so the classpath would remain that of B, and the run would file with
ClassNotFound errors.

Yasumoto/commons,nkhuyu/commons,foursquare/commons-old,jsirois/commons,abel-von/commons,cevaris/commons,Yasumoto/commons,jsirois/commons,pombredanne/commons,nkhuyu/commons,brutkin/commons,ericzundel/commons,VaybhavSharma/commons,WCCCEDU/twitter-commons,brutkin/commons,WCCCEDU/twitter-commons,ericzundel/commons,imsut/commons,jsirois/commons,atollena/commons,cevaris/commons,brutkin/commons,cevaris/commons,WCCCEDU/twitter-commons,abel-von/commons,ericzundel/commons,cevaris/commons,VaybhavSharma/commons,foursquare/commons-old,abel-von/commons,abel-von/commons,atollena/commons,imsut/commons,atollena/commons,nkhuyu/commons,VaybhavSharma/commons,nkhuyu/commons,ericzundel/commons,pombredanne/commons,atollena/commons,pombredanne/commons,nkhuyu/commons,VaybhavSharma/commons,abel-von/commons,atollena/commons,VaybhavSharma/commons,Yasumoto/commons,jsirois/commons,ericzundel/commons,pombredanne/commons,WCCCEDU/twitter-commons,pombredanne/commons,Yasumoto/commons,WCCCEDU/twitter-commons,jsirois/commons,cevaris/commons,foursquare/commons-old,imsut/commons,brutkin/commons,brutkin/commons,Yasumoto/commons