ci: fix server provision shell quoting

jenkins/Jenkinsfile.production-server-provision

@@ -287,7 +287,8 @@ BASH
             read_env_value() {
               local file="$1"
               local key="$2"
-              local line value
+              local line value quote_char
+              quote_char='"'
 
               if [[ ! -f "${file}" ]]; then
                 return
@@ -296,10 +297,9 @@ BASH
               while IFS= read -r line || [[ -n "${line}" ]]; do
                 if [[ "${line}" == "${key}="* ]]; then
                   value="${line#*=}"
-                  value="$(printf "%s" "${value}" | tr -d "\\r")"
-                  if [[ "${value}" == \"* && "${value}" == *\" ]]; then
-                    value="${value#\"}"
-                    value="${value%\"}"
+                  value="$(printf "%s" "${value}" | tr -d "\r")"
+                  if [[ ${#value} -ge 2 && "${value:0:1}" == "${quote_char}" && "${value: -1}" == "${quote_char}" ]]; then
+                    value="${value:1:${#value}-2}"
                   fi
                   printf "%s" "${value}"
                   return