systemd-systemctl: parse unit files more correctly

systemd-systemctl: parse unit files more correctly

Old script failed to parse unit files containing comments like

| #Alias=some-alias

or whitespaces like

| WantedBy = foo

correctly.  Patch changes script to interpret keywords only when they
are at the beginning of a line and ignores whitespaces before the '='.

(From OE-Core rev: 443e75ee2c0e9a62df997aef24855bce54d39177)

Signed-off-by: Enrico Scholz <enrico.scholz@sigma-chemnitz.de>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>