Remove the m2mconstants.cpp from sources.mk as it was deleted from git.

Author: TeroJaasko

sources.mk

@@ -1,12 +1,11 @@
 SRCS += \
 	source/m2mbase.cpp \
-	source/m2mconstants.cpp \
 	source/m2mdevice.cpp \
-        source/m2mfirmware.cpp \
+	source/m2mfirmware.cpp \
 	source/m2minterfacefactory.cpp \
 	source/m2minterfaceimpl.cpp \
 	source/m2mnsdlinterface.cpp \
-        source/m2mobject.cpp \
+	source/m2mobject.cpp \
 	source/m2mobjectinstance.cpp \
 	source/m2mreporthandler.cpp \
 	source/m2mresource.cpp \