[Java] Fix warnings in build script when trying to find cargo.
[Java] Fix warnings in build script when trying to find cargo.

real-logic/simple-binary-encoding,real-logic/simple-binary-encoding,PKRoma/simple-binary-encoding,real-logic/simple-binary-encoding,marksantos/simple-binary-encoding,marksantos/simple-binary-encoding,real-logic/simple-binary-encoding,marksantos/simple-binary-encoding,real-logic/simple-binary-encoding,PKRoma/simple-binary-encoding,marksantos/simple-binary-encoding,PKRoma/simple-binary-encoding,marksantos/simple-binary-encoding,marksantos/simple-binary-encoding,PKRoma/simple-binary-encoding,marksantos/simple-binary-encoding,marksantos/simple-binary-encoding,PKRoma/simple-binary-encoding,real-logic/simple-binary-encoding,PKRoma/simple-binary-encoding,PKRoma/simple-binary-encoding,real-logic/simple-binary-encoding