kpi: Fix naming of Measurement fields related to IP Throughput

    DRB.IPThpVol   ->  DRB.IPVol	(no "Thp" inside)
    DRB.IPThpTime  ->  DRB.IPTime	(no "Thp" inside

TS 32.450 and TS 32.425 defines those names as in corrected variants -
please see corresponding references in the code for details.

It was my thinko in dc1d5481 (kpi: Start of the package) to use "Thp" in
the names.

kpi.py

@@ -178,11 +178,11 @@ class Measurement(np.void):
         # TODO mean -> total + npkt?
         #('DRB.IPLatDl.QCI',                Ttime),     # s         4.4.5.1  32.450:6.3.2   NOTE not ms
 
-        # DRB.IPThpX.QCI = DRB.IPThpVolX.QCI / DRB.IPThpTimeX.QCI
-        ('DRB.IPThpVolDl.QCI',              np.int64),  # bit       4.4.6.1  32.450:6.3.1   NOTE not kbit
-        ('DRB.IPThpVolUl.QCI',              np.int64),  # bit       4.4.6.2  32.450:6.3.1   NOTE not kbit
-        ('DRB.IPThpTimeDl.QCI',             Ttime),     # s
-        ('DRB.IPThpTimeUl.QCI',             Ttime),     # s
+        # DRB.IPThpX.QCI = DRB.IPVolX.QCI / DRB.IPTimeX.QCI         4.4.6.1-2 32.450:6.3.1
+        ('DRB.IPVolDl.QCI',                 np.int64),  # bit       4.4.6.3  32.450:6.3.1   NOTE not kbit
+        ('DRB.IPVolUl.QCI',                 np.int64),  # bit       4.4.6.4  32.450:6.3.1   NOTE not kbit
+        ('DRB.IPTimeDl.QCI',                Ttime),     # s         4.4.6.5  32.450:6.3.1   NOTE not ms
+        ('DRB.IPTimeUl.QCI',                Ttime),     # s         4.4.6.6  32.450:6.3.1   NOTE not ms
 
         ('RRU.CellUnavailableTime.CAUSE',   Ttime),     # s         4.5.6
 

kpi_test.py

@@ -34,7 +34,7 @@ def test_Measurement():
     _('X.Tstart')                       # time
     _('RRC.ConnEstabAtt.sum')           # Tcc
     _('DRB.PdcpSduBitrateDl.sum')       # float32
-    _('DRB.IPThpVolDl.sum')             # int64
+    _('DRB.IPVolDl.sum')                # int64
     # everything automatically
     for name in m.dtype.names:
         _(name)