MAGETWO-52660: Improve performance of static assets deployment

- MAGETWO-57913: Mysql connections is lost if forked process

Author: mslabko

lib/internal/Magento/Framework/View/Asset/LockerProcess.php

@@ -59,7 +59,6 @@ public function __construct(Filesystem $filesystem)
 
     /**
      * @inheritdoc
-     * @throws FileSystemException
      */
     public function lockProcess($lockName)
     {
@@ -94,14 +93,18 @@ public function unlockProcess()
      * Check whether generation process has already locked
      *
      * @return bool
-     * @throws FileSystemException
      */
     private function isProcessLocked()
     {
         if ($this->tmpDirectory->isExist($this->lockFilePath)) {
-            $lockTime = (int) $this->tmpDirectory->readFile($this->lockFilePath);
-            if ((time() - $lockTime) >= self::MAX_LOCK_TIME) {
-                $this->tmpDirectory->delete($this->lockFilePath);
+            try {
+                $lockTime = (int)$this->tmpDirectory->readFile($this->lockFilePath);
+                if ((time() - $lockTime) >= self::MAX_LOCK_TIME) {
+                    $this->tmpDirectory->delete($this->lockFilePath);
+
+                    return false;
+                }
+            } catch (FileSystemException $e) {
 
                 return false;
             }