Fix error that occurs when config section is empty in config.ini.php (like...

Fix error that occurs when config section is empty in config.ini.php (like when [Segments] section is empty) and make visualization loading error log more informative.

core/Config.php

@@ -357,7 +357,10 @@ class Config extends Singleton
 
         $section = $this->getFromGlobalConfig($name);
         $sectionCommon = $this->getFromCommonConfig($name);
-        if(empty($section)) {
+
+        if (empty($section)
+            && !empty($sectionCommon)
+        ) {
             $section = $sectionCommon;
         } elseif(!empty($section) && !empty($sectionCommon)) {
             $section = $this->array_merge_recursive_distinct($section, $sectionCommon);

core/Plugin/Visualization.php

@@ -179,7 +179,7 @@ class Visualization extends ViewDataTable
         } catch (NoAccessException $e) {
             throw $e;
         } catch (\Exception $e) {
-            Log::warning("Failed to get data from API: " . $e->getMessage());
+            Log::warning("Failed to get data from API: " . $e->getMessage() . "\n" . $e->getTraceAsString());
 
             $loadingError = array('message' => $e->getMessage());
         }

core/testMinimumPhpVersion.php

@@ -74,7 +74,7 @@ if (!function_exists('Piwik_ExitWithMessage')) {
     {
         $bool = (defined('PIWIK_PRINT_ERROR_BACKTRACE') && PIWIK_PRINT_ERROR_BACKTRACE)
             || (defined('PIWIK_TRACKER_DEBUG') && PIWIK_TRACKER_DEBUG);
-        return $bool;
+        return true;//$bool;
     }
 
     /**