bee download should remove relicts on download failure

[wwwutz]

[BEE] => entering bee_getsources() ..
[BEE] fetching https://github.com/golang/tools/archive/refs/tags/v0.13.0.tar.gz
--2023-09-08 09:52:58--  https://github.com/golang/tools/archive/refs/tags/v0.13.0.tar.gz
Resolving github.com... 140.82.121.4
Connecting to github.com|140.82.121.4|:443... connected.
HTTP request sent, awaiting response... 302 Found
Location: https://codeload.github.com/golang/tools/tar.gz/refs/tags/v0.13.0 [following]
--2023-09-08 09:52:59--  https://codeload.github.com/golang/tools/tar.gz/refs/tags/v0.13.0
Resolving codeload.github.com... 140.82.121.10
Connecting to codeload.github.com|140.82.121.10|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [application/x-gzip]
Saving to: ‘/scratch/local/bee-root/golang-tools/files/v0.13.0.tar.gz’

     0K .......... .......... .......... .......... .......... 56.6K
    50K .......... .......... .......... .......... .......... 45.4K
   100K .......... .......... .......... .......... .......... 26.0M
   150K .......... .......... .......... .......... .......... 38.7K
   200K .......... .......... .......... .......... .......... 16.8M
   250K .......... .......... .......... .......... .......... 74.8K
   300K ....                                                   12.7K=4.3s

2023-09-08 09:54:05 (71.3 KB/s) - Read error at byte 311296 (Connection timed out).Giving up.

-rw-r--r-- 1 root root 311296 Sep  8 09:53 /scratch/local/bee-root/golang-tools/files/v0.13.0.tar.gz
[BEE] <= leaving bee_getsources() ..
[BEE] => entering bee_extract() ..
[BEE]  -> extracting main source /scratch/local/bee-root/golang-tools/files/v0.13.0.tar.gz ..
[BEE] tar xof /scratch/local/bee-root/golang-tools/files/v0.13.0.tar.gz -C /scratch/local/bee-root/golang-tools/golang-tools-0.13.0-0/source --strip-components 0

gzip: stdin: unexpected end of file
tar: Unexpected EOF in archive
tar: Unexpected EOF in archive
tar: Error is not recoverable: exiting now

the downloaded empty file should be removed since a cursor-up-return retry will fail.

[BEE] => entering bee_getsources() ..
[BEE] fetching https://github.com/golang/tools/archive/refs/tags/v0.13.0.tar.gz
File ‘/scratch/local/bee-root/golang-tools/files/v0.13.0.tar.gz’ already there; not retrieving.
-rw-r--r-- 1 root root 311296 Sep  8 09:53 /scratch/local/bee-root/golang-tools/files/v0.13.0.tar.gz
[BEE] <= leaving bee_getsources() ..
[BEE] => entering bee_extract() ..
[BEE]  -> extracting main source /scratch/local/bee-root/golang-tools/files/v0.13.0.tar.gz ..
[BEE] tar xof /scratch/local/bee-root/golang-tools/files/v0.13.0.tar.gz -C /scratch/local/bee-root/golang-tools/golang-tools-0.13.0-0/source --strip-components 0

gzip: stdin: unexpected end of file
tar: Unexpected EOF in archive
tar: Unexpected EOF in archive
tar: Error is not recoverable: exiting now