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

tridonic-com/mbed-client,tridonic-com/mbed-client,tridonic-com/mbed-client,ARMmbed/mbed-client,ARMmbed/mbed-client,ARMmbed/mbed-client