Fixed issues found by PVS Studio static analyzer

Author: sadko4u

src/main/gl/Surface.cpp

@@ -379,7 +379,7 @@ namespace lsp
 
                 buf     = serialize_clipping(buf);
                 buf     = serialize_color(buf, 1.0f, 1.0f, 1.0f, a);
-                buf     = serialize_texture(buf, t);
+                serialize_texture(buf, t);
 
                 return make_command(index, C_TEXTURE);
             }
@@ -409,7 +409,7 @@ namespace lsp
 
                 buf     = serialize_clipping(buf);
                 buf     = serialize_color(buf, color);
-                buf     = serialize_texture(buf, t);
+                serialize_texture(buf, t);
 
                 return make_command(index, C_TEXTURE);
             }

src/main/gl/TextAllocator.cpp

@@ -145,13 +145,14 @@ namespace lsp
                         NULL,
                         TEXT_ATLAS_SIZE, TEXT_ATLAS_SIZE,
                         0, gl::TEXTURE_ALPHA8);
+                    if (res != STATUS_OK)
+                        return NULL;
                 }
 
                 res = pTexture->set_subimage(
                     data,
                     rect->nLeft, rect->nTop, rect->nWidth, rect->nHeight,
                     stride);
-
                 if (res != STATUS_OK)
                     return NULL;