fixed unassigned value to a intent(out) variable in parse_header

[degawa]

Thank you, @14NGiestas and @jvdp1, for fixing issue #706 I reported.

Although you solved the issue (any value is not assigned to an intent(out) argument) found in get_descriptor, I discovered that the same problem still exists in parse_header called in get_descriptor.

I am sending this pull request to fix the issue. I would be happy if you reviewed the pull request.
This pull request fixes the failure of test_npy.

stdlib>fpm test test_npy --compiler nagfor --profile release --flag "-fpp"
Project is up to date
# Testing: npy
  Starting read-rdp-r2 ... (1/21)    
       ... read-rdp-r2 [FAILED]      
  Message: Reading of npy file failed
  Starting read-rdp-r3 ... (2/21)    
       ... read-rdp-r3 [FAILED]      
  Message: Reading of npy file failed
  Starting read-rsp-r1 ... (3/21)    
       ... read-rsp-r1 [FAILED]      
  Message: Reading of npy file failed
  Starting read-rsp-r2 ... (4/21)    
       ... read-rsp-r2 [FAILED]      
  Message: Reading of npy file failed
  Starting write-rdp-r2 ... (5/21)   
       ... write-rdp-r2 [FAILED]     
  Message: Reading of npy file failed
  Starting write-rsp-r2 ... (6/21)   
       ... write-rsp-r2 [FAILED]     
  Message: Reading of npy file failed
  Starting write-i2-r4 ... (7/21)    
       ... write-i2-r4 [FAILED]

7 test(s) failed!
ERROR STOP
<ERROR> Execution failed for object " test_npy.exe "
<ERROR>*cmd_run*:stopping due to failed executions
STOP 1

>fpm test test_npy --compiler nagfor --profile release --flag "-fpp"
Project is up to date
# Testing: npy
  Starting read-rdp-r2 ... (1/21)
       ... read-rdp-r2 [PASSED]
  Starting read-rdp-r3 ... (2/21)
       ... read-rdp-r3 [PASSED]
  Starting read-rsp-r1 ... (3/21)
       ... read-rsp-r1 [PASSED]
  Starting read-rsp-r2 ... (4/21)
       ... read-rsp-r2 [PASSED]
  Starting write-rdp-r2 ... (5/21)
       ... write-rdp-r2 [PASSED]
  Starting write-rsp-r2 ... (6/21)
       ... write-rsp-r2 [PASSED]
  Starting write-i2-r4 ... (7/21)
       ... write-i2-r4 [PASSED]

[jvdp1]

Thank you @degawa for this fix.

[jvdp1]

Thank you. I'll merge it.