Set library name to match Windows expectations.
Set library name to match Windows expectations.

Back to libwebm.lib from webm.lib.

Change-Id: I6ced362c987a7b5d3d56365a1ed53de7bf9f849b

Suvarna1488/webm.libwebm,kalli123/webm.libwebm,zofuthan/libwebm,felipebetancur/libwebm,Acidburn0zzz/webm.libwebm,Maria1099/webm.libwebm,iniwf/webm.libwebm,ericmckean/webm.libwebm,abwiz0086/webm.libwebm,zofuthan/libwebm,webmproject/libwebm,matanbs/webm.libwebm,reimaginemedia/webm.libwebm,gshORTON/webm.libwebm,webmproject/libwebm,webmproject/libwebm,kim42083/webm.libwebm,kleopatra999/webm.libwebm,felipebetancur/libwebm