resource-c: fixed a compiler warning.
murphy-db: sizeof(int*) -> sizeof(int) as reported by static analysis.
common: fix a possible NULL pointer error.
resource-native: do not use memory before assert.
resource-dbus: do not use memory before testing for NULL.
resource-client: fix possible NULL pointer bug.
lua-decision: do not crash if no error message set.

Function bridge expects every caller object to set a string
error message if the call fails, even if the return type is
set to boolean. Still, there shouldn't be a crash if the error
message is not set.