Segmentation fault in `get_pandora_connection`, when a login configuration file exists for the user.

[TCLamnidis]

The recommended way for mysql to store and provide authentication credentials during connection is to create a configuration file that contains the information in an obfuscated way. This information is then stored in a file named ~/.mylogin.cnf, which gets automatically picked up when running an SQL query.

Currently, when such a file is present, sidora.core::get_pandora_connection creates a segmentation error:

> sidora.core::get_pandora_connection("/home/thiseas_christos_lamnidis/Software/github/Schiffels-Popgen/MICROSCOPE-processing-pipeline/.credentials")

 *** caught segfault ***
address 0x10, cause 'memory not mapped'

Traceback:
 1: connection_create(host, username, password, dbname, as.integer(port),     unix.socket, as.integer(client.flag), group, default.file,     ssl.key, ssl.cert, ssl.ca, ssl.capath, ssl.cipher, timeout,     reconnect)
 2: .local(drv, ...)
 3: DBI::dbConnect(RMariaDB::MariaDB(), host = creds[1], port = creds[2],     user = creds[3], password = creds[4], db = "pandora")
 4: DBI::dbConnect(RMariaDB::MariaDB(), host = creds[1], port = creds[2],     user = creds[3], password = creds[4], db = "pandora")
 5: sidora.core::get_pandora_connection("/home/thiseas_christos_lamnidis/Software/github/Schiffels-Popgen/MICROSCOPE-processing-pipeline/.credentials")

Renaming the ~/mylogin.cnf file to something else fixed the issue.

This suggests that DBI::dbConnect implicitly calls mysql, which loads the configuration file, causing the segfault.

Maybe we should allow users to specify a login-path in get_pandora_connection, instead of a credential file, to allow usage with such a .cnf file.