Review Request 8068937: jdeps shows "not found" if target class has no reference other than its own package

[Mandy Chung]

http://cr.openjdk.java.net/~mchung/jdk9/webrevs/8068937/webrev.00/
This simple patch fixes a couple jdeps issues.  It makes sure a parsed 
class is added to the class list even if there is no reference other 
than its own package which is filtered by default, exclude itself from 
the summary dependences and also remove duplicates from the input paths 
and -classpath option.

Mandy