luna-service2.pc.in: Fix Requires.private format

:Release Notes:
Newer pkgconfig 0.28 is more strict than 0.25 and detecting
luna-service2 fails.

:Detailed Notes:
Space as separator is required in version specifier:
"PmLogLib >= 3.0.0"

PmLogLib was added in https://g2g.palm.com/4598

pkg-config-0.25 from dylan just ignores invalid line:
pkg-config --print-requires-private luna-service2

pkg-config-0.28 from dora shows error:
pkg-config --print-requires-private luna-service2
Package PmLogLib>=3.0.0 was not found in the pkg-config search path.
Perhaps you should add the directory containing `PmLogLib>=3.0.0.pc'
to the PKG_CONFIG_PATH environment variable
Package 'PmLogLib>=3.0.0', required by 'luna-service2', not found

And --exists call fails in 0.28 while it was ok in 0.25
pkg-config-0.25 from dylan:
pkg-config --exists luna-service2; echo $?
0

pkg-config-0.28 from dora:
pkg-config --exists luna-service2; echo $?
1

After adding space it works correctly in both:
pkg-config-0.25 from dylan:
pkg-config --print-requires-private luna-service2
glib-2.0
gthread-2.0
cjson
PmLogLib >= 3.0.0

pkg-config-0.28 from dora:
pkg-config --print-requires-private luna-service2
glib-2.0
gthread-2.0
cjson
PmLogLib >= 3.0.0

:Testing Performed:
Only build tested.

:QA Notes:
No change to image.

:Issues Addressed:
[ANG-329] Ongoing metadata improvement/cleanup work

Open-webOS-DCO-1.0-Signed-off-by: Martin Jansa <martin.jansa@lge.com>
Change-Id: I9c59dd73d9a3fefe85c6f7a76c697413045aed28
Reviewed-on: https://g2g.palm.com/4709
Reviewed-by: DCO Verification
Reviewed-by: Anatolii Sakhnik <anatolii.sakhnik@lge.com>
Reviewed-by: Martin Jansa <Martin.Jansa@lge.com>
Tested-by: Martin Jansa <Martin.Jansa@lge.com>