qwt: Adjust exclusion of docs

Note:

QWT is nowadays an extension for QT5. The old libs
'libqwt' and 'libqwtmathml' will be removed since they are
unused in the system. IMHO packages (if any) still using
the former qwt should be fixed inplace.

qwt.be0

@@ -10,7 +10,7 @@ PATCHURL[0]=""
 
 # BEE_BUILDTYPE=
 
-EXCLUDE=( $(pkg-config QtCore --variable=prefix)/doc )
+EXCLUDE=( $(pkg-config Qt5Core --variable=prefix)/doc )
 
 build_in_sourcedir