Fix Ubuntu detection

public/detect_linux.sh

@@ -9,19 +9,21 @@ elif [ -f /etc/lsb-release ]; then
   . /etc/lsb-release
   DISTNAME=$(echo ${DISTRIB_ID} | awk '{print tolower($0)}')
   DISTVER=${DISTRIB_RELEASE}
-  if [ "$DISTNAME" = "linuxmint" ]; then
-    if [ "$DISTVER" = "19" ] || [ "$DISTVER" = "19.1" ]; then
-      DISTNAME=ubuntu
-      DISTVER=18.04
+  if [ "$DISTNAME" != "ubuntu" ]; then
+    if [ "$DISTNAME" = "linuxmint" ]; then
+      if [ "$DISTVER" = "19" ] || [ "$DISTVER" = "19.1" ]; then
+        DISTNAME=ubuntu
+        DISTVER=18.04
+      fi
+    elif [ "$DISTNAME" = "elementary" ]; then
+      if [ "$DISTVER" = "5.0" ]; then
+        DISTNAME=ubuntu
+        DISTVER=18.04
+      fi
+    else
+      DISTNAME=unknown
+      DISTVER=
     fi
-  elif [ "$DISTNAME" = "elementary" ]; then
-    if [ "$DISTVER" = "5.0" ]; then
-      DISTNAME=ubuntu
-      DISTVER=18.04
-    fi
-  else
-    DISTNAME=unknown
-    DISTVER=
   fi
 elif [ -f /etc/debian_version ]; then
   DISTNAME=debian