Libbeat panic when float32 value returned in metricset

[iahmedov]

• Version:
  libbeat 7.0.0-alpha1 [72de9ed]

• Operating System:
  Linux

• Steps to Reproduce:

func (m *MetricSet) Fetch() (common.MapStr, error) {
  return common.MapStr{
    "value": float32(1),
  }, nil
}

Whats happening:

panic: interface conversion: interface {} is float32, not float64

goroutine 38 [running]:
github.com/elastic/beats/libbeat/common.normalizeValue(0x26aa620, 0x3ada1a0, 0xc42025fc10, 0x3, 0xa, 0x253f9f0, 0x25353d2, 0x26e0ae0, 0x25340d3, 0x2790a40)
	/home/ixtiyor/projects/golang/src/github.com/elastic/beats/libbeat/common/event.go:156 +0x2125
github.com/elastic/beats/libbeat/common.normalizeMap(0xc420298c00, 0xc42025fc10, 0x2, 0xa, 0x0, 0x0, 0x0, 0x0)
	/home/ixtiyor/projects/golang/src/github.com/elastic/beats/libbeat/common/event.go:47 +0x1c0
github.com/elastic/beats/libbeat/common.normalizeValue(0x29d5300, 0xc420298c00, 0xc42025fc10, 0x2, 0xa, 0x26c2ae0, 0xc420152e60, 0x0, 0x0, 0x0)
	/home/ixtiyor/projects/golang/src/github.com/elastic/beats/libbeat/common/event.go:162 +0x148c
github.com/elastic/beats/libbeat/common.normalizeMap(0xc420299020, 0xc42025fc10, 0x1, 0xa, 0x0, 0x0, 0x0, 0x0)
	/home/ixtiyor/projects/golang/src/github.com/elastic/beats/libbeat/common/event.go:47 +0x1c0
github.com/elastic/beats/libbeat/common.normalizeValue(0x29d5300, 0xc420299020, 0xc42025fc10, 0x1, 0xa, 0x29d5300, 0xc420299200, 0x0, 0x0, 0x0)
	/home/ixtiyor/projects/golang/src/github.com/elastic/beats/libbeat/common/event.go:162 +0x148c
github.com/elastic/beats/libbeat/common.normalizeMap(0xc420298f90, 0xc42025fc10, 0x0, 0xa, 0x0, 0x0, 0x0, 0x0)
	/home/ixtiyor/projects/golang/src/github.com/elastic/beats/libbeat/common/event.go:47 +0x1c0