quickly fix a lint issue

Change-Id: Ic6fd120301127f0eb36faea60b91c4b565f2f299
diff --git a/voltha b/voltha
index 6ac1be7..09ab1d8 100755
--- a/voltha
+++ b/voltha
@@ -1041,7 +1041,7 @@
         RESULT=$?
         if [ "$RESULT" -ne 0 ]; then
             espin - "$THEX"
-            >&2 echo -e "${RED}${BOLD}${ERROR}ERROR: unable to download kubectl: $(tail $ERR_OUT)${NORMAL}"
+            >&2 echo -e "${RED}${BOLD}${ERROR}ERROR: unable to download kubectl: $(tail "$ERR_OUT")${NORMAL}"
             cat "$ERR_OUT" >> "$LOG"
             rm -rf $"ERR_OUT" "$GOPATH/bin/kubectl"
             exit 1
@@ -1079,7 +1079,7 @@
         RESULT=$?
         if [ $RESULT -ne 0 ]; then
             espin - "$THEX"
-            >&2 echo -e "${RED}${BOLD}${ERROR}ERROR: unable to download kind: $(tail $ERR_OUT)${NORMAL}"
+            >&2 echo -e "${RED}${BOLD}${ERROR}ERROR: unable to download kind: $(tail "$ERR_OUT")${NORMAL}"
             cat "$ERR_OUT" >> "$LOG"
             rm -rf $"ERR_OUT" "$GOPATH/bin/kind"
             exit 1
@@ -1129,7 +1129,7 @@
         RESULT=$?
         if [ $RESULT -ne 0 ]; then
             espin - "$THEX"
-            >&2 echo -e "${RED}${BOLD}${ERROR}ERROR: unable to download helm installer: $(tail $ERR_OUT)${NORMAL}"
+            >&2 echo -e "${RED}${BOLD}${ERROR}ERROR: unable to download helm installer: $(tail "$ERR_OUT")${NORMAL}"
             cat "$ERR_OUT" >> "$LOG"
             rm -rf "$INSTALL_HELM_BIN" "$ERR_OUT" "$GOPATH/bin/helm" "$GOPATH/bin/tiller"
             exit 1