Fix when the source path contains a space

direct/src/directscripts/packpanda.nsi

@@ -139,7 +139,7 @@ Section "${SMDIRECTORY}" SecCore
             File /nonfatal /r "${PANDA}\plugins\*.dlo"
             File /nonfatal /r "${PANDA}\plugins\*.mll"
             File /nonfatal /r "${PANDA}\plugins\*.mel"
-            File ${PSOURCE}\doc\INSTALLING-PLUGINS.TXT
+            File "${PSOURCE}\doc\INSTALLING-PLUGINS.TXT"
             SetOutPath $INSTDIR\pandac\input
             File /r "${PANDA}\pandac\input\*"
             SetOutPath $INSTDIR\bin