call r_anal_op_free after acquiring RAnalOp pointer

[bart1e]

In last PR I forgot to call r_anal_op_free after getting pointer to a new RAnalOp, so I'm fixing it now.

[codecov-io]

Codecov Report

Merging #14317 into master will decrease coverage by <.01%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master   #14317      +/-   ##
==========================================
- Coverage   37.81%   37.81%   -0.01%     
==========================================
  Files         950      950              
  Lines      305790   305793       +3     
==========================================
  Hits       115644   115644              
- Misses     190146   190149       +3

Impacted Files	Coverage Δ
libr/core/cmd_debug.c	21.98% <0%> (-0.03%)	⬇️

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