libvpd: Replace popen/pclose with secure variants
libvpd: Replace popen/pclose with secure variants

Replace the occurrence of popen() with spopen/spclose variants.

Signed-off-by: Janani Venkataraman <f56d6e31cd704fb274698b50a2e47c9c06a451e9@linux.vnet.ibm.com>
[Fixed memory leak - Vasant]
Signed-off-by: Vasant Hegde <a6d753843573f7bfed5075c1e875b0be8007a0ab@linux.vnet.ibm.com>

kamalesh-babulal/libvpd,kamalesh-babulal/libvpd,kamalesh-babulal/libvpd