Log error message if setting project quota ID fails

Otherwise, the only sign of what went wrong may be system_server
logging a "ServiceSpecificException".

Bug: 187079978
Change-Id: I59b2ba2b0e679dfd1ec1fd8fff6790256fbfdf29
diff --git a/Utils.cpp b/Utils.cpp
index 9ff7920..9b31f72 100644
--- a/Utils.cpp
+++ b/Utils.cpp
@@ -240,7 +240,12 @@
     }
 
     fsx.fsx_projid = projectId;
-    return ioctl(fd, FS_IOC_FSSETXATTR, &fsx);
+    ret = ioctl(fd, FS_IOC_FSSETXATTR, &fsx);
+    if (ret == -1) {
+        PLOG(ERROR) << "Failed to set project id on " << path;
+        return ret;
+    }
+    return 0;
 }
 
 int PrepareDirWithProjectId(const std::string& path, mode_t mode, uid_t uid, gid_t gid,