Added detection if this is a git based install or not. (#9379)

Not sure about the warning or text.

DO NOT DELETE THIS TEXT

#### Please note

> Please read this information carefully. You can run `./scripts/pre-commit.php` to check your code before submitting.

- [x] Have you followed our [code guidelines?](http://docs.librenms.org/Developing/Code-Guidelines/)

#### Testers

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LibreNMS/Validations/Dependencies.php

@@ -38,6 +38,12 @@ class Dependencies extends BaseValidation
      */
     public function validate(Validator $validator)
     {
+        # if git is not installed, do not assume composer is either
+        if (!is_git_install()) {
+            $validator->ok("Installed from package; no Composer required");
+            return;
+        }
+
         $composer_output = trim(shell_exec($validator->getBaseDir() . '/scripts/composer_wrapper.php --version'));
         $found = preg_match(
             '/Composer.*(\d+\.\d+\.\d+(-RC\d*|-beta\d?|-alpha\d+)?)/',

LibreNMS/Validations/Updates.php

@@ -36,6 +36,11 @@ class Updates extends BaseValidation
 {
     public function validate(Validator $validator)
     {
+        if (!is_git_install()) {
+            $validator->warn('Non-git install, updates are manual or from package');
+            return;
+        }
+
         // if git is not available, we cannot do the other tests
         if (!check_git_exists()) {
             $validator->warn('Unable to locate git. This should probably be installed.');

LibreNMS/Validations/User.php

@@ -59,6 +59,10 @@ class User extends BaseValidation
             }
         }
 
+        # if no git, then we probably have different permissions by design
+        if (!is_git_install()) {
+            return;
+        }
 
         // Let's test the user configured if we have it
         if (Config::has('user')) {

includes/common.php

@@ -1134,7 +1134,7 @@ function version_info($remote = false)
 {
     global $config;
     $output = array();
-    if (check_git_exists() === true) {
+    if (is_git_install() && check_git_exists()) {
         if ($remote === true && $config['update_channel'] == 'master') {
             $api = curl_init();
             set_curl_proxy($api);
@@ -1715,6 +1715,12 @@ function set_numeric($value, $default = 0)
     return $value;
 }
 
+function is_git_install()
+{
+    $install_dir = Config::get('install_dir', realpath(__DIR__ . '/..'));
+    return file_exists("$install_dir/.git");
+}
+
 function check_git_exists()
 {
     exec('git > /dev/null 2>&1', $response, $exit_code);