Move the bits sanity checking a bit higher in the function

Saves some time and makes the code simpler as we have to delete one
thing less

poppler/Gfx.cc

diff --git a/poppler/Gfx.cc b/poppler/Gfx.cc
index 6f06f6c..a2d1db0 100644
--- a/poppler/Gfx.cc
+++ b/poppler/Gfx.cc
@@ -4407,6 +4407,9 @@
       }
     }
   } else {
+    if (bits == 0) {
+      goto err1;
+    }
 
     // get color space and color map
     dict->lookup("ColorSpace", &obj1);
@@ -4479,10 +4482,6 @@
       obj1.free();
       dict->lookup("D", &obj1);
     }
-    if (bits == 0) {
-      delete colorSpace;
-      goto err2;
-    }
     colorMap = new GfxImageColorMap(bits, &obj1, colorSpace);
     obj1.free();
     if (!colorMap->isOk()) {