[FIRRTL] Don't put names on constants

[darthscsi]

We are getting things like:

      %c0_ui2 = firrtl.constant 0 : !firrtl.uint<2> {name = "_count_reg_32_redundantReg_r_wrappedData"}
      %c0_ui4 = firrtl.constant 0 : !firrtl.uint<4> {name = "_count_reg_16_redundantReg_r_wrappedData"}
      %c0_ui1 = firrtl.constant 0 : !firrtl.uint<1> {name = "sources_with_cancel_0_2_lateCancel"}
      %c1_ui3 = firrtl.constant 1 : !firrtl.uint<3> {name = "r_d_bits_opcode"}
      %c1_ui1 = firrtl.constant 1 : !firrtl.uint<1> {name = "overflow_1"}
      %c1_ui2 = firrtl.constant 1 : !firrtl.uint<2> {name = "out_arw_bits_burst"}

I don't think constants should ever have name attributes.