tests: exit with legal value

The call to exit needs a natural value
as argument, change -1 to 1.

tests/06-script-base/04-test-result-visualization.sh

@@ -7,18 +7,18 @@ TEST_CODE_DIR=code-result-visualization
 make -C ${TEST_CODE_DIR} clean
 make -C ${TEST_CODE_DIR}
 
-${CONTIKI}/examples/benchmarks/result-visualization/run-analysis.py ${TEST_CODE_DIR}/00-result-visualization.1.scriptlog > analysis.log || exit -1
+${CONTIKI}/examples/benchmarks/result-visualization/run-analysis.py ${TEST_CODE_DIR}/00-result-visualization.1.scriptlog > analysis.log || exit 1
 
 # check that some packets were sent and all were received
-grep "PDR=100" analysis.log || exit -1
+grep "PDR=100" analysis.log || exit 1
 
 # check that PDF files are created
-ls plot_charge.pdf || exit -1
-ls plot_duty_cycle_joined.pdf || exit -1
-ls plot_duty_cycle.pdf || exit -1
-ls plot_par.pdf || exit -1
-ls plot_pdr.pdf || exit -1
-ls plot_rpl_switches.pdf || exit -1
+ls plot_charge.pdf || exit 1
+ls plot_duty_cycle_joined.pdf || exit 1
+ls plot_duty_cycle.pdf || exit 1
+ls plot_par.pdf || exit 1
+ls plot_pdr.pdf || exit 1
+ls plot_rpl_switches.pdf || exit 1
 
 # success
 exit 0