Quit the script when we hit hard errors

a found a few other points where we talk about exiting and re-running
the script once fixed, but never actually exit. So i'm adding-in the
missing exits, and updating any existing exits to make sure we return a
failing return code to the shell

upgrade.php

@@ -149,7 +149,7 @@
     echo "!!!!!!!!!!!!!!!!!!!!!!!!! ABORTING THE UPGRADER !!!!!!!!!!!!!!!!!!!!!!\n";
     echo "Please correct the issues above in ".getcwd()."/.env and try again.\n";
     echo "--------------------------------------------------------\n";
-    exit;
+    exit(1);
 }
 
 
@@ -168,7 +168,7 @@
     echo "Snipe-IT requires PHP versions between ".$php_min_works." and ".$php_max_wontwork.".\n";
     echo "Please install a compatible version of PHP and re-run this script again. \n";
     echo "!!!!!!!!!!!!!!!!!!!!!!!!! ABORTING THE UPGRADER !!!!!!!!!!!!!!!!!!!!!!\n";
-    exit;
+    exit(1);
 }
 
 echo "Checking Required PHP extensions... \n\n";
@@ -256,7 +256,7 @@
     echo "ABORTING THE INSTALLER  \n";
     echo "Please install the extensions above and re-run this script.\n";
     echo "--------------------------------------------------------\n";
-    exit;
+    exit(1);
 } else {
     echo $ext_installed."\n";
 
@@ -311,6 +311,7 @@
     echo "--------------------- !! ERROR !! ----------------------\n";
     echo "Please check the permissions on the directories above and re-run this script.\n";
     echo "------------------------- :( ---------------------------\n\n";
+    exit(1);
 }