[processing] fix substitution of the original layers in GDAL commands

(cherry picked from commit 89774ab)

Author: alexbruy

python/plugins/processing/algs/gdal/GdalAlgorithm.py

@@ -26,6 +26,7 @@
 __revision__ = '$Format:%H$'
 
 import os
+import re
 
 from qgis.PyQt.QtGui import QIcon
 
@@ -58,7 +59,9 @@ def processAlgorithm(self, progress):
                     c = c.replace(layer.source(), exported)
                     if os.path.isfile(layer.source()):
                         fileName = os.path.splitext(os.path.split(layer.source())[1])[0]
-                        c = c.replace(' ' + fileName + ' ', ' ' + exportedFileName + ' ')
+                        c = re.sub('[\s]{}[\s]'.format(fileName),  ' ' + exportedFileName + ' ', c)
+                        c = re.sub('[\s]{}'.format(fileName),  ' ' + exportedFileName, c)
+                        c = re.sub('["\']{}["\']'.format(fileName),  "'" + exportedFileName + "'", c)
 
             commands[i] = c
         GdalUtils.runGdal(commands, progress)