raise the correct error if the flac module won't work...

warn when it is not available..

[git-p4: depot-paths = "//depot/": change = 1674]

flac.py

@@ -43,7 +43,12 @@ except OSError:
 	    array.array('h', [ inbuf[chanmap[x % nchan]][x / nchan] for x in
 	    xrange(blksize * nchan)])
 
-flaclib = CDLL('libFLAC.so')
+try:
+	flaclib = CDLL('libFLAC.so')
+except OSError, e:
+	import warnings
+	warnings.warn('libFLAC.so not installed.  FLAC decoding not available.')
+	raise ImportError(str(e))
 
 # Defines