support/dependencies: check PATH does not carry a \n

support/dependencies: check PATH does not carry a \n

... otherwise it fails spectacularly as soon as PATH is referenced in a
package rule (i.e. very soon, fortunately):

    >>> host-lzip 1.18 Downloading
    /bin/bash: -c: line 0: unexpected EOF while looking for matching `"'
    /bin/bash: -c: line 1: syntax error: unexpected end of file

Fixes # 9886.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Ciro Santilli <ciro.santilli@gmail.com>
[Thomas: fix typo in message, use tabs for indentation.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>