fix(quickget): find qemu-img

- close #1224
- close #1229
- close #1234

quickget

@@ -3397,6 +3397,12 @@ if [ ! -e "${CURL}" ]; then
 fi
 CURL_VERSION=$("${CURL}" --version | head -1 | cut -d' ' -f2)
 
+QEMU_IMG=$(command -v qemu-img)
+if [ ! -x "${QEMU_IMG}" ]; then
+    echo "ERROR! qemu-img not found. Please make sure qemu-img is installed."
+    exit 1
+fi
+
 #TODO: Deprecate `list`, `list_csv`, and `list_json` in favor of `--list`, `--list-csv`, and `--list-json`
 case "${1}" in
     --download|-download)