on TravisCI, install curl => required for some tests
on TravisCI, install curl => required for some tests

stlankes/HermitCore,stlankes/HermitCore,RWTH-OS/HermitCore,stlankes/HermitCore,RWTH-OS/HermitCore,stlankes/HermitCore,RWTH-OS/HermitCore,stlankes/HermitCore,RWTH-OS/HermitCore,RWTH-OS/HermitCore,stlankes/HermitCore,RWTH-OS/HermitCore