cmd: Fix cmd's mishandling of quote-enclosed command strings

[testbot at testbot.winehq.org]

Hi,

While running your changed tests on Windows, I think I found new failures.
Being a bot and all I'm not very good at pattern recognition, so I might be
wrong, but could you please double-check?
Full results can be found at
http://testbot.winehq.org/JobDetails.pl?Key=3778

Your paranoid android.


=== WNT4WSSP6 (32 bit) ===
batch.c:177: Test failed: unexpected char 0x74 position 0 in line 49 (got 'test file.txt.fake', wanted 'testfile.txt.fake')
batch.c:188: Test failed: unexpected end of output in line 49, expected 0x74

=== W2KPROSP4 (32 bit) ===
batch.c:177: Test failed: unexpected char 0x74 position 0 in line 49 (got 'test file.txt.fake', wanted 'testfile.txt.fake')
batch.c:188: Test failed: unexpected end of output in line 49, expected 0x74

=== WXPPROSP3 (32 bit) ===
batch.c:177: Test failed: unexpected char 0x74 position 0 in line 49 (got 'test file.txt.fake', wanted 'testfile.txt.fake')
batch.c:188: Test failed: unexpected end of output in line 49, expected 0x74

=== W2K3R2SESP2 (32 bit) ===
batch.c:177: Test failed: unexpected char 0x74 position 0 in line 49 (got 'test file.txt.fake', wanted 'testfile.txt.fake')
batch.c:188: Test failed: unexpected end of output in line 49, expected 0x74

=== WVISTAADM (32 bit) ===
batch.c:177: Test failed: unexpected char 0x74 position 0 in line 49 (got 'test file.txt.fake', wanted 'testfile.txt.fake')
batch.c:188: Test failed: unexpected end of output in line 49, expected 0x74

=== W2K8SE (32 bit) ===
batch.c:177: Test failed: unexpected char 0x74 position 0 in line 49 (got 'test file.txt.fake', wanted 'testfile.txt.fake')
batch.c:188: Test failed: unexpected end of output in line 49, expected 0x74

=== W7PRO (32 bit) ===
batch.c:177: Test failed: unexpected char 0x74 position 0 in line 49 (got 'test file.txt.fake', wanted 'testfile.txt.fake')
batch.c:188: Test failed: unexpected end of output in line 49, expected 0x74

=== W7PROX64 (32 bit) ===
batch.c:177: Test failed: unexpected char 0x74 position 0 in line 49 (got 'test file.txt.fake', wanted 'testfile.txt.fake')
batch.c:188: Test failed: unexpected end of output in line 49, expected 0x74

=== W7PROX64 (64 bit) ===
batch.c:177: Test failed: unexpected char 0x74 position 0 in line 49 (got 'test file.txt.fake', wanted 'testfile.txt.fake')
batch.c:188: Test failed: unexpected end of output in line 49, expected 0x74