delete useless import

Author: yiming-tang-cs

edu.cuny.hunter.streamrefactoring.core/src/edu/cuny/hunter/streamrefactoring/core/analysis/Stream.java

@@ -56,7 +56,6 @@
 import com.ibm.wala.ipa.callgraph.impl.FakeRootMethod;
 import com.ibm.wala.ipa.callgraph.impl.FakeWorldClinitMethod;
 import com.ibm.wala.ipa.callgraph.propagation.InstanceKey;
-import com.ibm.wala.ipa.callgraph.propagation.cfa.CallStringContext;
 import com.ibm.wala.ipa.cha.ClassHierarchyException;
 import com.ibm.wala.ipa.cha.IClassHierarchy;
 import com.ibm.wala.shrikeCT.InvalidClassFileException;