Fix travis-fuzz upgrade handling

fuzz/travis-fuzz.sh

@@ -1,11 +1,11 @@
 #!/bin/bash
-cargo install honggfuzz
-set +e
+set -e
+cargo install --force honggfuzz
 for TARGET in fuzz_targets/*; do
     FILENAME=$(basename $TARGET)
 	FILE="${FILENAME%.*}"
 	HFUZZ_BUILD_ARGS="--features honggfuzz_fuzz" HFUZZ_RUN_ARGS="-N1000000 --exit_upon_crash -v" cargo hfuzz run $FILE
-	if [ -f hfuzz_workspace/$FILE/HONGGFUZZ.REPORT.TXT ]; then 
+	if [ -f hfuzz_workspace/$FILE/HONGGFUZZ.REPORT.TXT ]; then
 		cat hfuzz_workspace/$FILE/HONGGFUZZ.REPORT.TXT
 		for CASE in hfuzz_workspace/$FILE/SIG*; do
 			cat $CASE | xxd -p