Fix issue with trimming in deblender

The deblender was trimming some Footprints of any pixels that were
zero or less, rather than dropping only pixels in the image that
were identically zero in the image.

python/lsst/meas/deblender/plugins.py

@@ -53,7 +53,7 @@ def clipFootprintToNonzeroImpl(foot, image):
         spanX1 = span.getX1()
         xMin = spanX0 if spanX0 >= x0 else x0
         xMax = spanX1 if spanX1 <= xImMax else xImMax
-        xarray = np.arange(xMin, xMax+1)[arr[y-y0, xMin-x0:xMax-x0+1] > 0]
+        xarray = np.arange(xMin, xMax+1)[arr[y-y0, xMin-x0:xMax-x0+1] != 0]
         if len(xarray) > 0:
             newSpans.append(afwGeom.Span(y, xarray[0], xarray[-1]))
     # Time to update the SpanSet