Fix issues with $PATH and netdatacli detection. (netdata#19371)

- Account for Debian/Ubuntu still not including sbin directories in user
  $PATH.
- Report an inability to detect netdatacli location instead of trying to
  invoke an empty string when claiming.

packaging/installer/kickstart.sh

@@ -20,12 +20,26 @@ KICKSTART_SOURCE="$(
     echo "$(pwd -P)/${self##*/}"
 )"
 DEFAULT_PLUGIN_PACKAGES=""
-PATH="${PATH}:/usr/local/bin:/usr/local/sbin"
 REPOCONFIG_DEB_VERSION="4-1"
 REPOCONFIG_RPM_VERSION="4-1"
 START_TIME="$(date +%s)"
 STATIC_INSTALL_ARCHES="x86_64 armv7l armv6l aarch64 ppc64le"
 
+# ======================================================================
+# Properly sort out inconsistencies in `$PATH` across distros
+#
+# Debian and Ubuntu still don’t include sbin directories for regular
+# users (even though the distinction is all but pointless at this point in
+# time), and a number of distros don’t include the standard paths under
+# `/usr/local` either.
+
+for dir in /usr/sbin /sbin /usr/local/bin /usr/local/sbin ; do
+  case ":${PATH}:" in
+    *:${dir}:*) ;;
+    *) PATH="${PATH}:${dir}" ;;
+  esac
+done
+
 # ======================================================================
 # URLs used throughout the script
 
@@ -1279,7 +1293,11 @@ write_claim_config() {
   run_as_root mv -f "${claim_config}.tmp" "${claim_config}" || return 1
 
   if [ -z "${NETDATA_CLAIM_NORELOAD}" ]; then
-    run_as_root "${netdatacli}" reload-claiming-state || return 1
+    if [ -n "${netdatacli}" ]; then
+      run_as_root "${netdatacli}" reload-claiming-state || return 1
+    else
+      warning "Unable to find the netdatacli binary, the agent must be restarted to finish claiming"
+    fi
   fi
 }