Fix Sconscript error

SConscript

@@ -6,12 +6,13 @@ cwd     = GetCurrentDir()
 # The set of source files associated with this SConscript file.
 src     = Glob('src/*.c')
 
-if GetDepend('PROTOBUF_C_USING_ENCODE_DECODE_EXAMPLE'):
+if GetDepend('PROTOBUF_C_USING_EXAMPLE'):
 	src    += Glob('examples/amessage.pb-c.c')
+
+if GetDepend('PROTOBUF_C_USING_ENCODE_DECODE_EXAMPLE'):
 	src    += Glob('examples/amessage_encode_decode.c')
 
 if GetDepend('PROTOBUF_C_USING_ENCODE_DECODE_FILE_EXAMPLE'):
-	src    += Glob('examples/amessage.pb-c.c')
 	src    += Glob('examples/amessage_encode_to_file.c')
 	src    += Glob('examples/amessage_decode_from_file.c')
 
@@ -21,6 +22,6 @@ path   += [cwd + '/examples']
 
 LOCAL_CCFLAGS = ''
 
-group = DefineGroup('libann', src, depend = ['PKG_USING_PROTOBUF_C'], CPPPATH = path, LOCAL_CCFLAGS = LOCAL_CCFLAGS)
+group = DefineGroup('protobuf-c', src, depend = ['PKG_USING_PROTOBUF_C'], CPPPATH = path, LOCAL_CCFLAGS = LOCAL_CCFLAGS)
 
 Return('group')