move /usr/local/bin check after platform check

`/usr/local/bin` is an os-specific path that must exist on your $PATH. This change moves the check confirming that to _after_ the OS and platform checks to allow for it to bail earlier on windows with a more helpful error message

install-standalone.sh

@@ -17,11 +17,6 @@
 
   echoerr() { echo "\$@" 1>&2; }
 
-  if [[ ! ":$PATH:" == *":/usr/local/bin:"* ]]; then
-    echoerr "Your path is missing /usr/local/bin, you need to add this to use this installer."
-    exit 1
-  fi
-
   if [ "\$(uname)" == "Darwin" ]; then
     OS=darwin
   elif [ "\$(expr substr \$(uname -s) 1 5)" == "Linux" ]; then
@@ -43,6 +38,11 @@
     exit 1
   fi
 
+  if [[ ! ":$PATH:" == *":/usr/local/bin:"* ]]; then
+    echoerr "Your path is missing /usr/local/bin, you need to add this to use this installer."
+    exit 1
+  fi
+
   mkdir -p /usr/local/lib
   cd /usr/local/lib
   rm -rf heroku