Fix UnicodeDecodeError when OpenSSL is not found

[purplesyringa]

Fixes #2180

[HelloZeroNet]

It would be better to figure out how to decode the result properly. I was unable to reproduce the error as I have english system installed, but I did tried this way:

import subprocess

print("Default encoding:")
proc = subprocess.Popen(
    "chcp", shell=True, stderr=subprocess.STDOUT,
    stdout=subprocess.PIPE
)
print(proc.stdout.read())

cmd = """powershell Write-Host \xe1rv\xedzt\u0171r\u0151"""
for code_page in [852, 65001]:
	subprocess.call("chcp %s" % code_page, shell=True)
	proc = subprocess.Popen(
	    cmd, shell=True, stderr=subprocess.STDOUT,
	    stdout=subprocess.PIPE
	)
	back = proc.stdout.read()
	print("- Running:", cmd)
	print("Back:", back)
	print("Back.decode(errors='replace'):", back.decode(errors="replace"))

Output:

Default encoding:
b'Active code page: 852\r\n'
Active code page: 852
- Running: powershell Write-Host árvíztűrő
Back: b'\xa0rv\xa1zt\xfbr\x8b\n'
Back.decode(errors='replace'): �rv�zt�r�

Active code page: 65001
- Running: powershell Write-Host árvíztűrő
Back: b'\xc3\xa1rv\xc3\xadzt\xc5\xb1r\xc5\x91\n'
Back.decode(errors='replace'): árvíztűrő

Based on this it would be more proper fix add

if sys.platform.startswith("win"):
   subprocess.call("chcp 65001", shell=True)

To beginning of the function or to main.py as it effects other subprocess executions as well.

[purplesyringa]

Ok, that makes sense. It's still worth merging this PR until we come up with a better solution.

[purplesyringa]

For the record: this is now replaced with a better fix