Avoid spaces in the trace file names.

Having spaces in the trace file names introduces slashes in the
file names and not able to pull the file names with the slashes
from the device.So avoid having spaces while constructing the
trace file names.

Bug : b/65737738

Change-Id: Ie1971566586f77d18b17722ce0e3cc9ef3ebfdd3
(cherry picked from commit 3f04fb1b)